diff --git a/CHANGES b/CHANGES
index b8f167f5f..cad3b9b0a 100644
--- a/CHANGES
+++ b/CHANGES
@@ -10,6 +10,9 @@ Incompatible changes
 * #4460: extensions which stores any data to environment should return the
   version of its env data structure as metadata.  In detail, please see
   :ref:`ext-metadata`.
+* The default value of :confval:`epub_author` and :confval:`epub_publisher` are
+  changed from ``'unknown'`` to the value of :confval:`author`.  This is same as
+  a ``conf.py`` file sphinx-build generates.
 
 Deprecated
 ----------
diff --git a/doc/config.rst b/doc/config.rst
index 9e92f083e..2e9ddf07c 100644
--- a/doc/config.rst
+++ b/doc/config.rst
@@ -1414,8 +1414,8 @@ the `Dublin Core metadata <http://dublincore.org/>`_.
 
 .. confval:: epub_author
 
-   The author of the document.  This is put in the Dublin Core metadata.  The
-   default value is ``'unknown'``.
+   The author of the document.  This is put in the Dublin Core metadata.  It
+   defaults to the :confval:`author` option.
 
 .. confval:: epub_contributor
 
@@ -1436,8 +1436,8 @@ the `Dublin Core metadata <http://dublincore.org/>`_.
 .. confval:: epub_publisher
 
    The publisher of the document.  This is put in the Dublin Core metadata.  You
-   may use any sensible string, e.g. the project homepage.  The default value is
-   ``'unknown'``.
+   may use any sensible string, e.g. the project homepage.  The defaults to the
+   :confval:`author` option.
 
 .. confval:: epub_copyright
 
diff --git a/sphinx/builders/epub3.py b/sphinx/builders/epub3.py
index c98c4b853..2a1b743e0 100644
--- a/sphinx/builders/epub3.py
+++ b/sphinx/builders/epub3.py
@@ -231,9 +231,9 @@ def setup(app):
     app.add_config_value('epub_theme', 'epub', 'html')
     app.add_config_value('epub_theme_options', {}, 'html')
     app.add_config_value('epub_title', lambda self: self.html_title, 'html')
-    app.add_config_value('epub_author', 'unknown', 'html')
+    app.add_config_value('epub_author', lambda self: self.author, 'html')
     app.add_config_value('epub_language', lambda self: self.language or 'en', 'html')
-    app.add_config_value('epub_publisher', 'unknown', 'html')
+    app.add_config_value('epub_publisher', lambda self: self.author, 'html')
     app.add_config_value('epub_copyright', lambda self: self.copyright, 'html')
     app.add_config_value('epub_identifier', 'unknown', 'html')
     app.add_config_value('epub_scheme', 'unknown', 'html')