diff --git a/Mrbgems-FAQ.md b/Mrbgems-FAQ.md
index 47fdfbd..3978065 100644
--- a/Mrbgems-FAQ.md
+++ b/Mrbgems-FAQ.md
@@ -1,6 +1,11 @@
 ## What's mrbgems?
 
-(To be written...)
+mrbgems is a library manager for mruby.
+
+It likes RubyGems for CRuby, but while RubyGems is dynamic, mrbgems is static.
+mrbgems is used during building mruby, unlike RubyGems, which is used after ruby is installed.
+
+In detail, see https://github.com/mruby/mruby/blob/master/doc/mrbgems/README.md
 
 ## How to add mrbgems?