diff --git a/ChangeLog.md b/ChangeLog.md
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,3 +1,7 @@
+## 0.6.3.0
+
+- Add Int8 type as SQL constant int value. (e.g. MySQL)
+
 ## 0.6.2.0
 
 - Make InsertQuery type as PreparedNoFetch instance.
diff --git a/relational-query.cabal b/relational-query.cabal
--- a/relational-query.cabal
+++ b/relational-query.cabal
@@ -1,5 +1,5 @@
 name:                relational-query
-version:             0.6.2.0
+version:             0.6.3.0
 synopsis:            Typeful, Modular, Relational, algebraic query engine
 description:         This package contiains typeful relation structure and
                      relational-algebraic query building DSL which can
diff --git a/src/Database/Relational/Query/Pure.hs b/src/Database/Relational/Query/Pure.hs
--- a/src/Database/Relational/Query/Pure.hs
+++ b/src/Database/Relational/Query/Pure.hs
@@ -21,7 +21,7 @@
   ) where
 
 import Data.Monoid (mconcat)
-import Data.Int (Int16, Int32, Int64)
+import Data.Int (Int8, Int16, Int32, Int64)
 import Data.ByteString (ByteString)
 import qualified Data.ByteString.Lazy as LB
 import Data.Text (Text)
@@ -78,6 +78,10 @@
 -- | String interface of 'showConstantTermsSQL''.
 showConstantTermsSQL :: ShowConstantTermsSQL a => a -> [String]
 showConstantTermsSQL =  map showStringSQL . showConstantTermsSQL'
+
+-- | Constant SQL terms of 'Int8'.
+instance ShowConstantTermsSQL Int8 where
+  showConstantTermsSQL' = intTermsSQL
 
 -- | Constant SQL terms of 'Int16'.
 instance ShowConstantTermsSQL Int16 where