To protect a rack shaft from an excessive external force, owing to the hitting of the rack shaft to a stopper resulting from a large bending amount of the rack shaft, when an excessive external force is operated to the rack shaft.

In this electric power steering device, a rack tooth 5a is formed on the front surface of one end of a rack shaft 5 extended in the car width direction, a pinion 4 is engaged to the rack tooth 5a, a rack guide 50 pushing out the rear surface of the rack shaft is installed, a screw part is formed at the other end of the rack shaft, a nut is installed to the screw part, and an auxiliary torque according to a steering torque is to be added to the rack shaft through the nut. The rack guide is provided at the center side of the car body by the pinion, the rack shaft, the pinion, the rack guide, and the nut are housed in a steering gear box 21 in a bulk, and a stopper 22a to limit the bending of the one end of the rack shaft is provided in the steering gear box 21.