diff --git a/src/lib/time.lisp b/src/lib/time.lisp
new file mode 100644
index 0000000..16380dc
--- /dev/null
+++ b/src/lib/time.lisp
@@ -0,0 +1,26 @@
+(defpackage #:hp/lib/time
+  (:use #:cl)
+  (:import-from #:local-time
+                #:reread-timezone-repository
+                #:find-timezone-by-location-name
+                #:parse-timestring
+                #:format-timestring)
+  (:export #:datetime
+           #:jp-datetime))
+(in-package #:hp/lib/time)
+
+(reread-timezone-repository)
+(setf local-time:*default-timezone*
+      (find-timezone-by-location-name "Asia/Tokyo"))
+
+(defun datetime (timestring)
+  (format-timestring nil
+                     (parse-timestring timestring)
+                     :format '(:year "-" (:month 2) "-" (:day 2) " "
+                               (:hour 2) ":" (:min 2))))
+
+(defun jp-datetime (timestring)
+  (format-timestring nil
+                     (parse-timestring timestring)
+                     :format '(:year "年" :month "月" :day "日" " "
+                               :hour "時" :min "分")))