To provide an electronic breaker with an electrical leak detection function capable of detecting electrical leak without the necessity of providing a separate space for the detection and without considerably changing the constitution of the breaker.

Load side terminals 4 composed of three terminals are disposed on the front surface, and power source side terminals 3 composed of three terminals are disposed on the back surface. A part of electrical paths 1 formed of copper bars 15 reaching to the load side terminals 4 is composed of straight portions 15S disposed in parallel within one flat surface. At right and left places between the three straight portions 15S, a first magnetism detection element 7A and a second magnetism detection element 7B for detecting magnetism generated by electrial path currents are disposed. A controller 8 detects an imbalance of the electrical path currents from the detected magnetism information. When detecting an imbalance, the controller 8 determines that an electrical leak has occurred and disconnects the electrical path.