Abstract: An easy-to-assemble electric power steering device for automotive vehicles is provided which includes an electric motor, a controller, and a torque transmission mechanism. The controller controls a steering assist torque outputted by the motor. The torque transmission mechanism work to transmit the output of the motor to a steering shaft. The steering device also includes a support member which work to support the steering shaft and the controller within a shell. Specifically, the controller is not mounted directly on an inner wall of the shell, but retained by the support member, thus facilitating ease of electrical connection between electrical parts installed on the support member and a substrate of the controller after the substrate is mounted on the support member.