The utility model relates to an electricity larceny detector and belongs to the technical field of electricity larceny detection. According to the technical scheme, the device is composed of a measuring end and a data receiving end which are matched with each other, wherein the measuring end comprises a measuring end shell (6), a first power supply (9), a Rogowski coil (1), an integral amplifier (2), an AD converter (3), a first comparator (4) and a first wireless transceiver (5); And the data receiving end comprises a receiving end shell (18), a comparator II (11), a wireless transceiver II (12), a display screen (13), a power supply II (14) and a key (15). The beneficial effects of the utility model are that the 10kV line current of the user is measured and compared with the secondary current on the rear platform of the electricity acquisition system of the power supply enterprise to confirm whether the user steals electricity or not, and then measures such as comprehensive inspection and the like are taken in a targeted manner to lock electricity stealing evidences and avoid fishing needle type inspection of the seas; The electricity larceny detection device is convenient to useand accurate in detection aiming at various electricity larceny modes.