diff --git a/Data/UnixTime/Diff.hs b/Data/UnixTime/Diff.hs
--- a/Data/UnixTime/Diff.hs
+++ b/Data/UnixTime/Diff.hs
@@ -48,7 +48,7 @@
 -- | Calculating difference between two 'UnixTime'.
 --
 -- >>> UnixTime 100 2000 `diffUnixTime` UnixTime 98 2100
--- UnixDiffTime 1 999900
+-- UnixDiffTime {udtSeconds = 1, udtMicroSecnods = 999900}
 --
 
 diffUnixTime :: UnixTime -> UnixTime -> UnixDiffTime
@@ -65,7 +65,7 @@
 -- | Creating difference from seconds.
 --
 -- >>> secondsToUnixDiffTime 100
--- UnixDiffTime 100 0
+-- UnixDiffTime {udtSeconds = 100, udtMicroSecnods = 0}
 
 secondsToUnixDiffTime :: (Integral a) => a -> UnixDiffTime
 secondsToUnixDiffTime sec = UnixDiffTime (fromIntegral sec) 0
@@ -74,10 +74,10 @@
 -- | Creating difference from micro seconds.
 --
 -- >>> microSecondsToUnixDiffTime 12345678
--- UnixDiffTime 12 345678
+-- UnixDiffTime {udtSeconds = 12, udtMicroSecnods = 345678}
 --
 -- >>> microSecondsToUnixDiffTime (-12345678)
--- UnixDiffTime (-12) (-345678)
+-- UnixDiffTime {udtSeconds = -12, udtMicroSecnods = -345678}
 
 microSecondsToUnixDiffTime :: (Integral a) => a -> UnixDiffTime
 microSecondsToUnixDiffTime usec = calc (fromIntegral s) (fromIntegral u)
diff --git a/Data/UnixTime/Types.hs b/Data/UnixTime/Types.hs
--- a/Data/UnixTime/Types.hs
+++ b/Data/UnixTime/Types.hs
@@ -22,11 +22,11 @@
 -- Data structure for UnixTime diff.
 --
 -- >>> (3 :: UnixDiffTime) + 2
--- UnixDiffTime 5 0
+-- UnixDiffTime {udtSeconds = 5, udtMicroSecnods = 0}
 -- >>> (2 :: UnixDiffTime) - 5
--- UnixDiffTime (-3) 0
+-- UnixDiffTime {udtSeconds = -3, udtMicroSecnods = 0}
 -- >>> (3 :: UnixDiffTime) * 2
--- UnixDiffTime 6 0
+-- UnixDiffTime {udtSeconds = 6, udtMicroSecnods = 0}
 
 data UnixDiffTime = UnixDiffTime {
     -- | Seconds from 1st Jan 1970
diff --git a/unix-time.cabal b/unix-time.cabal
--- a/unix-time.cabal
+++ b/unix-time.cabal
@@ -1,5 +1,5 @@
 Name:                   unix-time
-Version:                0.1.7
+Version:                0.1.8
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3