diff --git a/docs/vfm.md b/docs/vfm.md
index 2b9cdd2..f558f91 100644
--- a/docs/vfm.md
+++ b/docs/vfm.md
@@ -401,6 +401,8 @@ It also outputs `<script>` for processing MathJax if `math` is enabled and the m
 
 Frontmatter is a way of defining metadata in Markdown (file) units. Write YAML at the beginning of the file.
 
+I'm using [js-yaml](https://www.npmjs.com/package/js-yaml) for parse in YAML. Schema is [JSON_SCHEMA](https://yaml.org/spec/1.2/spec.html#id2803231). 
+
 **VFM**
 
 ```yaml
diff --git a/src/plugins/metadata.ts b/src/plugins/metadata.ts
index 2c53cd1..00879fc 100644
--- a/src/plugins/metadata.ts
+++ b/src/plugins/metadata.ts
@@ -1,5 +1,5 @@
 import { Element } from 'hast';
-import { load as yaml } from 'js-yaml';
+import { JSON_SCHEMA, load as yaml } from 'js-yaml';
 import { FrontmatterContent, Literal } from 'mdast';
 import toString from 'mdast-util-to-string';
 import stringify from 'rehype-stringify';
@@ -101,7 +101,7 @@ const readTitleFromHeading = (tree: Node) => {
  */
 const mdast = () => (tree: Node, file: MetadataVFile) => {
   visit<FrontmatterContent>(tree, ['yaml'], (node) => {
-    const value = yaml(node.value);
+    const value = yaml(node.value, { schema: JSON_SCHEMA });
     if (typeof value === 'object') {
       file.data = {
         ...file.data,
diff --git a/tests/metadata.test.ts b/tests/metadata.test.ts
index 162fe1c..b3fab1e 100644
--- a/tests/metadata.test.ts
+++ b/tests/metadata.test.ts
@@ -251,3 +251,23 @@ link:
 `;
   expect(received).toBe(expected);
 });
+
+it('Do not convert date and time', () => {
+  const md = `---
+date: 2021-06-27
+date2: "2021-06-27"
+---`;
+  const received = stringify(md, { style: ['sample2.css', 'sample3.css'] });
+  const expected = `<!doctype html>
+<html>
+  <head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <meta name="date" content="2021-06-27">
+    <meta name="date2" content="2021-06-27">
+  </head>
+  <body></body>
+</html>
+`;
+  expect(received).toBe(expected);
+});
