To provide a closure detecting unit for a storage that can be externally mounted on the storage, monitor closure of a door of the storage to detect an illicit opening and improve its security by detecting whether the storage is kept in a non-monitored state.

The closure detecting unit for a storage is mounted on a position where the closure detecting unit can be mounted while the door of the storage is closed. The closure detecting unit comprises a clock section for starting to clock when the closure detecting unit stops detecting a closing state of the door after entering a designated identification code through an operating section, and a determining section for determining abnormality when the closing state of the door is not detected until, at the clock section, a designated time elapses. Thus, the illicit opening of the door and a non-monitored state of the storage can be prevented.