PURPOSE: To prevent the wear of a contact and to prevent the unstability of a steering by detecting a steering current and holding the current via a relay in accordance with the indication of the detected value.

CONSTITUTION: A battery 30 and a drive sensor 31 are electrically connected to a controller 20, and a main coil 25 of a holding relay 24 and the contact 22 of an openable relay 21 are disposed in series with each other in a circuit of a steering current for connecting the battery 30 to a motor 15 for driving an oil pump 14. An operation coil 23 for the contact 22 is through the controller 20, and the contact 27 of a reed relay 26 for detecting the steering current flowing through the coil 25 is electrically connected to apply the detection signal to the controller 20. The controller 20 closes the contact 22 by the signal from the sensor 31 and flows the steering current through the coil 25. The contact 27 is closed with this current, the relay 24 electrically connected to receive a signal of a drive sensor 31 time, and is released from self-holding in the relay 24 at the non-steering time.