To provide an electric power steering device for quickly returning to a state capable of assisting steering, by shortening charging time of an auxiliary power source, by supplying a regenerative current recirculated to the power source only to the auxiliary power source connected in parallel to a main power source.

This electric power steering device has the main power source composed of an on-vehicle generator 34 and an on-vehicle battery 26, a steering assisting motor 18 driven by the main power source and a motor driving circuit 13, and the auxiliary power sources 29 and 32 connected in parallel to the main power source and the motor driving circuit 13 and assisting an electric current made to flow to the motor 18, and controls the electric current flowing to the motor 18 based on steering torque detected by a torque sensor 10, and has a motor current detecting circuit 17 detecting the electric current flowing in the motor driving circuit 13 from the main power source and the auxiliary power sources 29 and 32, a relay driving circuit 15 and a relay contact point 15a cutting off the main power source from the auxiliary power sources 29 and 32 when the motor current detecting circuit 17 does not detect the electric current flowing in the motor driving circuit 13.