diff --git a/package.json b/package.json
index 118d2bb..d12ae7f 100644
--- a/package.json
+++ b/package.json
@@ -69,7 +69,7 @@
     "koaton-exporter": "^1.2.1",
     "mocha": "^4.0.1",
     "npm-run-all": "^4.1.1",
-    "nyc": "11.4.1",
+    "nyc": "13.3.0",
     "ps-tree": "^1.1.0"
   },
   "bin": {