There is provided a power steering apparatus comprising a torque sensor detecting a steering torque capable of discriminating a normal input and an inverse input without a torsion bar. An intermediate gear engaging with rack teeth provided in an outer surface of a rack shaft and a pinion provided in a lower portion of a pinion shaft is interposed between both the rack tooth and the pinion. A force applied to the pinion shaft is detected by a first force sensor, a force applied to a support shaft of the intermediate gear is detected by a second force sensor, and a torque detection value capable of discriminating the normal input and inverse input is calculated by a torque calculating unit to which outputs of both the sensors are given.