A rotating field sensor includes a first detection circuit that outputs a first signal indicating the intensity of a component of a rotating magnetic field in a first direction, a second detection circuit that outputs a second signal indicating the intensity of a component of the rotating magnetic field in a second direction, and an arithmetic circuit that calculates a detected angle value based on the first and second signals. Each of the first and second detection circuits includes at least one MR element row. Each MR element row is composed of a plurality of MR elements connected in series. Each MR element has a magnetization pinned layer. The plurality of MR elements forming each MR element row include one or more pairs of MR elements. Magnetization directions of the magnetization pinned layers in two MR elements making up a pair form a predetermined relative angle other than 0° and 180°.