To surely detect a sensor label even by electric waves, having a feeble electric field strength, specify a shoplifting and prevent the escape of a shoplifter.

In the shoplifting preventing device for a store provided with a revolving door at an entrance and an exit, transmitters for transmitting radio electric wave are provided ion respective partition plate constitution a plurality of blocks respectively and a receiver for receiving the radio wave and operating an alarm is provided on one sidewall on the inside of the store.