The present invention is to provide an electronic device capable of automatically resetting, which includes a main circuit system and an external circuit system. The main circuit system is able to send out a power supply state signal according to the voltage thereof and an activation state signal according to whether the main circuit system is properly activated. The external circuit system is able to receive the power supply state signal and the activation state signal, switch a switch between a turned-on state and a turned-off state for automatically cutting off electricity supplied to the main circuit system through the switch while the main circuit system is improperly activated and then supplying electricity to the main circuit system thereafter. Thus, whenever the electronic device is improperly activated, the electricity supplied to the main circuit system can be automatically cut off and then restored to reset the main circuit system automatically.