WordPress with my site

I have a blog on wordpress, for example www/blog.com – folder
and my site example.com, www/example.com – folder.

I try integrate worpress with my site. example.com/blog – must go to wordpress index page, and example.com/blog/post_name must go to wordpress post.

apache conf

<VirtualHost *:80>
    ServerName example.com
    DocumentRoot /var/www/example.com
    ServerAlias www.example.com
    Alias /blog /var/www/blog.com
    <Location /blog>
    </Location>
</VirtualHost>
<Directory /var/www/example.com>
    #code
</Directory>
<Directory /var/www/blog.com>
    #code
</Directory>

In worpress admin panel i change:
WordPress Address (URL) to example.com/blog
Site Address (URL) to example.com
Permalink Settings to /blog/%postname%/

When i go to example.com/blog it work fine, but when i type
example.com/blog/post_name i have 404 error.

Edit:
request example.com/blog go to wordpress directory, but example.com/blog/post_name go to example.com index.php