diff --git a/LayoutTests/ChangeLog b/LayoutTests/ChangeLog
index 1885fbe..cd9ea7b 100644
--- a/LayoutTests/ChangeLog
+++ b/LayoutTests/ChangeLog
@@ -1,3 +1,17 @@
+2019-05-12  Takashi Komori  <Takashi.Komori@sony.com>
+
+        [Curl] Suppress extra didReceiveAuthenticationChallenge call when accessing a server which checks basic auth.
+        https://bugs.webkit.org/show_bug.cgi?id=197650
+
+        Reviewed by Fujii Hironori.
+
+        * TestExpectations:
+        * http/tests/resources/basic-auth.php: Added.
+        * http/tests/ssl/curl/certificate-and-authentication-expected.txt: Added.
+        * http/tests/ssl/curl/certificate-and-authentication.html: Added.
+        * platform/wincairo-wk1/TestExpectations:
+        * platform/wincairo/TestExpectations:
+
 2019-05-11  Simon Fraser  <simon.fraser@apple.com>
 
         Overflow scroll that becomes non-scrollable should stop being composited
diff --git a/LayoutTests/TestExpectations b/LayoutTests/TestExpectations
index 18521e1..cdf8129 100644
--- a/LayoutTests/TestExpectations
+++ b/LayoutTests/TestExpectations
@@ -52,6 +52,7 @@
 http/tests/preload/viewport [ Skip ]
 http/tests/gzip-content-encoding [ Skip ]
 http/tests/cookies/same-site [ Skip ]
+http/tests/ssl/curl [ Skip ]
 system-preview [ Skip ]
 editing/images [ Skip ]
 pointerevents/ios [ Skip ]
diff --git a/LayoutTests/http/tests/resources/basic-auth.php b/LayoutTests/http/tests/resources/basic-auth.php
new file mode 100644
index 0000000..95dce5d
--- /dev/null
+++ b/LayoutTests/http/tests/resources/basic-auth.php
@@ -0,0 +1,10 @@
+<?php
+  if (!isset($_SERVER['PHP_AUTH_USER']) || !isset($_REQUEST['uid']) || ($_REQUEST['uid'] != $_SERVER['PHP_AUTH_USER'])) {
+   header('WWW-Authenticate: Basic realm="WebKit Test Realm"');
+   header('HTTP/1.0 401 Unauthorized');
+   echo 'Authentication canceled';
+   exit;
+  } else {
+   echo "User: {$_SERVER['PHP_AUTH_USER']}, password: {$_SERVER['PHP_AUTH_PW']}.";
+  }
+?>
diff --git a/LayoutTests/http/tests/ssl/curl/certificate-and-authentication-expected.txt b/LayoutTests/http/tests/ssl/curl/certificate-and-authentication-expected.txt
new file mode 100644
index 0000000..b51bdbd
--- /dev/null
+++ b/LayoutTests/http/tests/ssl/curl/certificate-and-authentication-expected.txt
@@ -0,0 +1,4 @@
+localhost:8443 - didReceiveAuthenticationChallenge - ProtectionSpaceAuthenticationSchemeHTTPBasic - Responding with user:
+
+PASS Certificate validation and basic authentication 
+
diff --git a/LayoutTests/http/tests/ssl/curl/certificate-and-authentication.html b/LayoutTests/http/tests/ssl/curl/certificate-and-authentication.html
new file mode 100644
index 0000000..3d69088
--- /dev/null
+++ b/LayoutTests/http/tests/ssl/curl/certificate-and-authentication.html
@@ -0,0 +1,42 @@
+<!DOCTYPE html>
+<html>
+<head>
+<!-- This is a test for https://bugs.webkit.org/show_bug.cgi?id=197650 -->
+<title>Certificate validation and basic authentication</title>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+</head>
+<body>
+<script>
+function with_iframe(url) {
+    return new Promise(function(resolve) {
+        var frame = document.createElement('iframe');
+        frame.className = 'test-iframe';
+        frame.src = url;
+        frame.onload = function() { resolve(frame); };
+        document.body.appendChild(frame);
+    });
+}
+
+async function doTest()
+{
+    assert_true(!!window.testRunner, "Test requires testRunner");
+
+    window.testRunner.setAllowsAnySSLCertificate(true);
+    window.testRunner.setHandlesAuthenticationChallenges(true);
+    window.testRunner.setAuthenticationUsername("user");
+    window.testRunner.setAuthenticationPassword("");
+
+    const currentCallbackCounts = window.testRunner.serverTrustEvaluationCallbackCallsCount;
+
+    const iframe = await with_iframe("https://localhost:8443/resources/basic-auth.php?uid=user");
+    iframe.remove();
+
+    assert_equals(window.testRunner.serverTrustEvaluationCallbackCallsCount - currentCallbackCounts, 1);
+}
+
+doTest().then(done, (e) => { assert_unreached("test failed: " + e); done(); });
+
+</script>
+</body>
+</html>
diff --git a/LayoutTests/platform/wincairo-wk1/TestExpectations b/LayoutTests/platform/wincairo-wk1/TestExpectations
index 54a9bb7..97a11f4 100644
--- a/LayoutTests/platform/wincairo-wk1/TestExpectations
+++ b/LayoutTests/platform/wincairo-wk1/TestExpectations
@@ -21,6 +21,7 @@
 http/tests/security/cookies/third-party-cookie-blocking-xslt.xml [ Skip ]
 
 # Server trust evaluation only supported in WK2.
+http/tests/ssl/curl/certificate-and-authentication.html [ Skip ]
 http/tests/ssl/iframe-upgrade.https.html [ Skip ]
 http/tests/ssl/mixedContent/insecure-websocket.html [ Failure ]
 http/tests/ssl/upgrade-origin-usage.html [ Failure ]
diff --git a/LayoutTests/platform/wincairo/TestExpectations b/LayoutTests/platform/wincairo/TestExpectations
index 3291973..4ee7e05e 100644
--- a/LayoutTests/platform/wincairo/TestExpectations
+++ b/LayoutTests/platform/wincairo/TestExpectations
@@ -948,6 +948,7 @@
 http/tests/security/cookies/third-party-cookie-blocking-user-action.html [ Pass ]
 http/tests/security/cookies/third-party-cookie-blocking-xslt.xml [ Pass ]
 
+http/tests/ssl/curl/certificate-and-authentication.html [ Pass ]
 http/tests/ssl/media-stream [ Skip ]
 
 [ Debug ] http/tests/storage/callbacks-are-called-in-correct-context.html [ Skip ]
diff --git a/Source/WebCore/ChangeLog b/Source/WebCore/ChangeLog
index 626c55f..880b4ca 100644
--- a/Source/WebCore/ChangeLog
+++ b/Source/WebCore/ChangeLog
@@ -1,3 +1,19 @@
+2019-05-12  Takashi Komori  <Takashi.Komori@sony.com>
+
+        [Curl] Suppress extra didReceiveAuthenticationChallenge call when accessing a server which checks basic auth.
+        https://bugs.webkit.org/show_bug.cgi?id=197650
+
+        Reviewed by Fujii Hironori.
+
+        When Curl port accesses a page which checks Basic Authentication credential and server trust challenge occurs,
+        Curl port calls extra didReceiveAuthenticationChallenge unnecessarily.
+        This is because Curl port discards information about allowed server trust challenge before in NetworkDataTaskCurl::restartWithCredential.
+
+        Test: http/tests/ssl/curl/certificate-and-authentication.html
+
+        * platform/network/curl/CurlRequest.h:
+        (WebCore::CurlRequest::isServerTrustEvaluationDisabled):
+
 2019-05-11  Simon Fraser  <simon.fraser@apple.com>
 
         Overflow scroll that becomes non-scrollable should stop being composited
diff --git a/Source/WebCore/platform/network/curl/CurlRequest.h b/Source/WebCore/platform/network/curl/CurlRequest.h
index d13766e..91d4dc9 100644
--- a/Source/WebCore/platform/network/curl/CurlRequest.h
+++ b/Source/WebCore/platform/network/curl/CurlRequest.h
@@ -74,6 +74,7 @@
     void invalidateClient();
     WEBCORE_EXPORT void setAuthenticationScheme(ProtectionSpaceAuthenticationScheme);
     WEBCORE_EXPORT void setUserPass(const String&, const String&);
+    bool isServerTrustEvaluationDisabled() { return m_shouldDisableServerTrustEvaluation; }
     void disableServerTrustEvaluation() { m_shouldDisableServerTrustEvaluation = true; }
     void setStartTime(const MonotonicTime& startTime) { m_requestStartTime = startTime; }
 
diff --git a/Source/WebKit/ChangeLog b/Source/WebKit/ChangeLog
index cdb9040..244ae3d 100644
--- a/Source/WebKit/ChangeLog
+++ b/Source/WebKit/ChangeLog
@@ -1,3 +1,13 @@
+2019-05-12  Takashi Komori  <Takashi.Komori@sony.com>
+
+        [Curl] Suppress extra didReceiveAuthenticationChallenge call when accessing a server which checks basic auth.
+        https://bugs.webkit.org/show_bug.cgi?id=197650
+
+        Reviewed by Fujii Hironori.
+
+        * NetworkProcess/curl/NetworkDataTaskCurl.cpp:
+        (WebKit::NetworkDataTaskCurl::restartWithCredential):
+
 2019-05-10  Chris Dumez  <cdumez@apple.com>
 
         [PSON] Prevent flashing when the process-swap is forced by the client
diff --git a/Source/WebKit/NetworkProcess/curl/NetworkDataTaskCurl.cpp b/Source/WebKit/NetworkProcess/curl/NetworkDataTaskCurl.cpp
index 36a6b39..77633ba 100644
--- a/Source/WebKit/NetworkProcess/curl/NetworkDataTaskCurl.cpp
+++ b/Source/WebKit/NetworkProcess/curl/NetworkDataTaskCurl.cpp
@@ -425,12 +425,13 @@
     ASSERT(m_curlRequest);
 
     auto previousRequest = m_curlRequest->resourceRequest();
+    auto shouldDisableServerTrustEvaluation = protectionSpace.authenticationScheme() == ProtectionSpaceAuthenticationSchemeServerTrustEvaluationRequested || m_curlRequest->isServerTrustEvaluationDisabled();
     m_curlRequest->cancel();
 
     m_curlRequest = createCurlRequest(WTFMove(previousRequest), RequestStatus::ReusedRequest);
     m_curlRequest->setAuthenticationScheme(protectionSpace.authenticationScheme());
     m_curlRequest->setUserPass(credential.user(), credential.password());
-    if (protectionSpace.authenticationScheme() == ProtectionSpaceAuthenticationSchemeServerTrustEvaluationRequested)
+    if (shouldDisableServerTrustEvaluation)
         m_curlRequest->disableServerTrustEvaluation();
     m_curlRequest->setStartTime(m_startTime);
     m_curlRequest->start();