The invention relates to an electricity stealing prevention device aiming contact electricity stealing and noncontact electricity stealing. The electricity stealing prevention device comprises a power supply, a strong magnetism monitoring module, a high frequency monitoring module, an entrance guard monitoring module, an alarm module and an alarm monitoring terminal. The power supply is used for supplying power to the whole device. The strong magnetism monitoring module is used for detecting a strong magnetism signal and transmitting the strong magnetism signal to the alarm module. The high frequency monitoring module is used for detecting a high-frequency signal and transmitting the high-frequency detection signal to the alarm module. The entrance guard monitoring module is used for detecting an entrance guard signal of an electric energy metering box and transmitting the detected entrance guard signal of the electric energy metering box to the alarm module. The alarm module is used for respectively receiving the strong magnetism signal, the high-frequency detection signal and the entrance guard signal of the electric energy metering box and outputting an alarm signal to the alarm monitoring terminal via a wireless mode so as to perform detection alarm. Automatic inspection and alarm for conventional electricity stealing, wireless high-frequency interference electricity stealing and strong magnetism interference electricity stealing can be realized.