PURPOSE: To display breaking of a main circuit only at the time of generation of leakage current by connecting a second switching element to a trip coil electrically in series, and the same to a leakage display coil and to a first switching element electrically in parallel.

CONSTITUTION: A first switching element Q1 is provided to work when a zero phase current transformer 1 detects leakage current of a main circuit. To the element Q1 a trip coil to actuate a breaking unit 5 and a leakage display coil 8 to actuate a leakage display in series. Further a second switching element Q2 is provided to work when an over-current transformer 7 detects over-current of the main circuit. The element Q2 is connected to the coil 2 electrically in series, and to the coil 8 and the element Q1 electrically in parallel. With such a constitution, leakage current when it occurs in the main circuit is detected by the transformer 1 and a breaking unit 5 and the leakage display are actuated through the element Q1 and coils 2, 8, but upon generation of over-current the coil 8 is not excitated through the element Q2 and the leakage display does not work.