To prevent formation of a closed loop between a motor and a motor driving circuit when a short circuit occurs in the motor driving circuit, to avoid heating generation, and to reduce power consumption.

This electric power steering gear is provided with a latching relay 12. The latching relay 12 is provided with a permanent magnet, and usually maintains the condition wherein a contact point for connecting/disconnecting a connection point 20U of a series circuit 10U to/from a U-phase coil 11U and a contact point 14V for connecting/disconnecting a connection point 20V of a series circuit 10V to/from a V-phase coil 11V are closed. When a short circuit failure occurs in the motor driving circuit, the contact points 14U and 14V are opened to disconnect between the connection point 20U of the series circuit 10U and the U-phase coil 11U and between the connection point 20V of the series circuit 10V and the V-phase coil 11V.