diff --git a/package-lock.json b/package-lock.json
index b624dbc..12e0aeb 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,7 +8,7 @@
       "version": "1.1.14",
       "license": "MIT",
       "dependencies": {
-        "@actions/core": "^1.2.6",
+        "@actions/core": "^1.4.0",
         "@actions/exec": "^1.0.4",
         "@actions/io": "^1.0.2",
         "@actions/tool-cache": "^1.6.1",
@@ -33,9 +33,9 @@
       }
     },
     "node_modules/@actions/core": {
-      "version": "1.2.6",
-      "resolved": "https://registry.npmjs.org/@actions/core/-/core-1.2.6.tgz",
-      "integrity": "sha512-ZQYitnqiyBc3D+k7LsgSBmMDVkOVidaagDG7j3fOym77jNunWRuYx7VSHa9GNfFZh+zh61xsCjRj4JxMZlDqTA=="
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/@actions/core/-/core-1.4.0.tgz",
+      "integrity": "sha512-CGx2ilGq5i7zSLgiiGUtBCxhRRxibJYU6Fim0Q1Wg2aQL2LTnF27zbqZOrxfvFQ55eSBW0L8uVStgtKMpa0Qlg=="
     },
     "node_modules/@actions/exec": {
       "version": "1.0.4",
@@ -9562,9 +9562,9 @@
   },
   "dependencies": {
     "@actions/core": {
-      "version": "1.2.6",
-      "resolved": "https://registry.npmjs.org/@actions/core/-/core-1.2.6.tgz",
-      "integrity": "sha512-ZQYitnqiyBc3D+k7LsgSBmMDVkOVidaagDG7j3fOym77jNunWRuYx7VSHa9GNfFZh+zh61xsCjRj4JxMZlDqTA=="
+      "version": "1.4.0",
+      "resolved": "https://registry.npmjs.org/@actions/core/-/core-1.4.0.tgz",
+      "integrity": "sha512-CGx2ilGq5i7zSLgiiGUtBCxhRRxibJYU6Fim0Q1Wg2aQL2LTnF27zbqZOrxfvFQ55eSBW0L8uVStgtKMpa0Qlg=="
     },
     "@actions/exec": {
       "version": "1.0.4",
diff --git a/package.json b/package.json
index 2600873..61ef898 100644
--- a/package.json
+++ b/package.json
@@ -39,7 +39,7 @@
   },
   "homepage": "https://github.com/peaceiris/actions-mdbook#readme",
   "dependencies": {
-    "@actions/core": "^1.2.6",
+    "@actions/core": "^1.4.0",
     "@actions/exec": "^1.0.4",
     "@actions/io": "^1.0.2",
     "@actions/tool-cache": "^1.6.1",