The rotation sensor includes a plurality of magnetic sensors for outputting a sine wave signal and a cosine wave signal corresponding to an electrical angle of rotation of the rotating body, and the magnetic sensors are arranged at equal intervals and in a circumferential direction of the rotating body apart from the outer periphery of the rotating body, and are fixed in position so as to detect a change in magnetic field caused by the change in the rotational position of the rotating body due to the rotation of the rotating body. The rotation sensor includes an arithmetic unit, which receives sine wave signals and cosine wave signals from a plurality of magnetic sensors, and adds and subtracts sine wave signals and cosine wave signals according to a predetermined rule, thereby cancels out the high-order components contained in sine wave signals and cosine wave signals.