PURPOSE: To perform the interception of a continuous rating current to a starter motor without fail, by making up a circuit structure so as to make no current flow into a suction coil when a transistor being turned on with a starter switch closed is turned off if making the starter switch open.

CONSTITUTION: With a starter switch 23 closed, a holding coil 1 is excited and a first moving iron core 2 is attracted, making a first connection circuit close by a first traveling contact 3 in response to movement of the said iron core 2. In addition, with this connection circuit closed, the suction coil 4 is excited, attracting a second moving iron core 5, and a pinion 25 is slidingly moved via a lever 24 whereby it is made so as to be engaged with a ring gear (unillustrated herein) of an internal combustion engine. And a second connection circuit is closed by a second traveling contact 6 is response to movement of the second iron core 5 whereby each starter motor (27 and 28) is energized with a continuous rating current. Likewise, in time of closing the starter switch 23, a transistor 30 is turned to ON, and an interval between one end of the suction coil 4 and the second connection circuit is connected together.