A current detecting device for detecting current flowing in a first electric wire arranged close to a second electric wire having a portion extending in a predetermined direction. The device comprises: a portion of the first electric wire extending at right angles to the second electric wire; a magnetic core arranged around the above portion of the first electric wire, the magnetic core having an axis thereof extending at right angles to the above portion of the second electric wire; and a magnetic-to-electric transducer associated with the magnetic core for generating an electric signal indicative of the intensity of a magnetic field generated around the above portion of the first electric wire by current flowing in the first electric wire.