diff --git a/Mighty.hs b/Mighty.hs
--- a/Mighty.hs
+++ b/Mighty.hs
@@ -34,6 +34,8 @@
 import System.Posix
 import Types
 import Utils
+import System.Date.Cache
+import Network.HTTP.Date
 
 ----------------------------------------------------------------
 
@@ -222,8 +224,9 @@
         -> IO ()
 single' opt route s rpt stt lgr getInfo mgr = reportDo rpt $ do
     myThreadId >>= setWarpThreadId stt
+    zdater <- initZoneDater
     runSettingsSocket setting s $ \req ->
-        fileCgiApp cspec filespec cgispec revproxyspec route req
+        fileCgiApp (cspec zdater) filespec cgispec revproxyspec route req
   where
     debug = opt_debug_mode opt
     setting = defaultSettings {
@@ -235,9 +238,10 @@
       , settingsHost        = HostAny
       }
     serverName = BS.pack $ opt_server_name opt
-    cspec = ClassicAppSpec {
+    cspec zdater = ClassicAppSpec {
         softwareName = serverName
       , logger = apatcheLogger lgr
+      , dater = zdater
       , statusFileDir = fromString $ opt_status_file_dir opt
       }
     filespec = FileAppSpec {
@@ -250,6 +254,10 @@
       }
     revproxyspec = RevProxyAppSpec {
         revProxyManager = mgr
+      }
+    initZoneDater = fst <$> clockDateCacher DateCacheConf {
+        getTime = epochTime
+      , formatDate = return . formatHTTPDate . epochTimeToHTTPDate
       }
 
 ----------------------------------------------------------------
diff --git a/mighttpd2.cabal b/mighttpd2.cabal
--- a/mighttpd2.cabal
+++ b/mighttpd2.cabal
@@ -1,5 +1,5 @@
 Name:                   mighttpd2
-Version:                2.7.2
+Version:                2.8.0
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             Kazu Yamamoto <kazu@iij.ad.jp>
 License:                BSD3
@@ -23,6 +23,7 @@
                       , blaze-html >= 0.5
                       , bytestring
                       , conduit
+                      , date-cache
                       , deepseq
                       , directory
                       , filepath