The invention discloses a dismounting monitoring device, which comprises a judging module, a switch module, a processor and a storage module, wherein the judging module is used for judging the validity of the dismounting; the switch module is used for sending discontinuing signals to the processor; the processor is used for recording illegal dismounting information after receiving the discontinuing signals; and the storage module is used for storing the illegal dismounting information. The invention also discloses a dismounting monitoring method. Through judging the validity of the dismounting, the invention uses the processor for recording and storing the illegal dismounting information in a discontinuing signal sending mode when the dismounting is illegal, so during the equipment maintenance, the illegal dismounting possibly suffered by the equipment can be obtained through invoking the stored information, the monitoring on the illegal dismounting can be effectively realized, and the responsibility among manufacturers, providers and users can be defined.