A pair of magnetic recording parts are axially spaced on a rotating shaft and a pair of magnetic heads for recording and reproducing a location signal are respectively opposed to the respective magnetic recording parts. Torque of the rotating shaft is calculated based on a quantity of a phase shift of the location signals reproduced by the respective magnetic heads and rotating speed of the rotating shaft is calculated based on a reproducing frequency of the location signal reproduced by one of the magnetic heads so that the magnetic recording parts and the magnetic heads serves as a sensor for detecting both torque and rotating speed. Thus, a number of parts of the sensor is lessened, being compacted with low cost.