diff --git a/lib/manager/circleci/extract.js b/lib/manager/circleci/extract.js
index 0d3b875837..151784b4ae 100644
--- a/lib/manager/circleci/extract.js
+++ b/lib/manager/circleci/extract.js
@@ -9,7 +9,7 @@ function extractDependencies(content) {
   const deps = [];
   let lineNumber = 0;
   for (const line of content.split('\n')) {
-    const match = line.match(/^\s*- image:\s*([^\s]+)\s*$/);
+    const match = line.match(/^\s*- image:\s*'?"?([^\s'"]+)'?"?\s*$/);
     if (match) {
       const currentFrom = match[1];
       const {
diff --git a/lib/manager/circleci/update.js b/lib/manager/circleci/update.js
index ac3c949fa1..99b5a093d3 100644
--- a/lib/manager/circleci/update.js
+++ b/lib/manager/circleci/update.js
@@ -7,7 +7,7 @@ function setNewValue(currentFileContent, upgrade) {
     logger.debug(`circleci.setNewValue: ${upgrade.newFrom}`);
     const lines = currentFileContent.split('\n');
     const lineToChange = lines[upgrade.lineNumber];
-    const imageLine = new RegExp(/^(\s*- image:\s*)[^\s]+(\s*)$/);
+    const imageLine = new RegExp(/^(\s*- image:\s*'?"?)[^\s'"]+('?"?\s*)$/);
     if (!lineToChange.match(imageLine)) {
       logger.debug('No image line found');
       return null;
diff --git a/test/_fixtures/circleci/config.yml b/test/_fixtures/circleci/config.yml
index c9856e8474..68f5e031c7 100644
--- a/test/_fixtures/circleci/config.yml
+++ b/test/_fixtures/circleci/config.yml
@@ -55,7 +55,7 @@ jobs:
   node-v4:
     <<: *node-base
     docker:
-      - image: node:4
+      - image: 'node:4'
   node-v6:
     <<: *node-base
     docker:
@@ -63,4 +63,4 @@ jobs:
   node-v8:
     <<: *node-base
     docker:
-      - image: node:8.9.0
+      - image: "node:8.9.0"