A power steering apparatus for power steering the steerable wheels of a vehicle is disclosed which includes a steering column having one end connected with a steering wheel and the other end operatively connected with the steerable wheels; a cylindrical housing surrounding the steering column and providing a space therebetween; a torque sensor disposed in the housing for detecting a steering torque exerted on the steering wheel by a driver; a conductor or lead line wound around the steering column and accommodated in the housing, the lead line having one end electrically connected to the torque sensor and the other end to terminals which are disposed outside the steering column; and a motor installed on the housing and operatively connected with the steering column for power assisting the steering effort exerted on the steering wheel by the driver, the motor being driven to run in accordance with the steering torque detected by the torque sensor. A rotation limiting mechanism is provided between the steering column and the housing for limiting the rotation of the steering column within a predetermined range.