A torque steering angle sensor, which is configured to be arranged on a coupling portion for a first rotary member and a second rotary member of an electrically assisted power steering device to be coupled together by a torsion bar having a torsional angle depending on a steering torque of a steering wheel, and which is configured to detect a steering angle and the steering torque of the steering wheel, comprising: an annular ring magnet provided with a plurality of magnetic poles (311, 312) having different polarities in a circumferential direction around a rotational axis of the first rotary member and the second rotary member, the annular ring magnet being configured to rotate together with the first rotary member; a plurality of magnetic path forming members (41,42) configured to form magnetic paths for a magnetic flux of the ring magnet, the magnetic path forming members being configured to vary in location relative to the plurality of magnetic poles of the ring magnet, depending on torsion of the torsion bar; one pair of magnetic flux collecting rings (51, 52) configured to collect the magnetic flux of the plurality of magnetic path forming members; a first magnetic field detecting element configured to detect a magnetic field strength between the one pair of magnetic flux collecting rings (51, 52); a non-rotary member for being not rotated by rotation of the first rotary member; a second magnetic field detecting element fixed to the non-rotary member, and located in such a manner as to receive a magnetic field from the ring magnet; a slide magnet for producing a magnetic field in a different direction from that of the magnetic field of the ring magnet in the second magnetic field detecting element; and a sliding mechanism configured to move the slide magnet toward or apart from the second magnetic field detecting element with the rotation of the first rotary member, characterised in that the second magnetic field detecting element is configured to be able to detect a magnetic field strength received from the ring magnet, and a magnetic field strength received from the slide magnet. an annular ring magnet provided with a plurality of magnetic poles (311, 312) having different polarities in a circumferential direction around a rotational axis of the first rotary member and the second rotary member, the annular ring magnet being configured to rotate together with the first rotary member; a plurality of magnetic path forming members (41,42) configured to form magnetic paths for a magnetic flux of the ring magnet, the magnetic path forming members being configured to vary in location relative to the plurality of magnetic poles of the ring magnet, depending on torsion of the torsion bar; one pair of magnetic flux collecting rings (51, 52) configured to collect the magnetic flux of the plurality of magnetic path forming members; a first magnetic field detecting element configured to detect a magnetic field strength between the one pair of magnetic flux collecting rings (51, 52); a non-rotary member for being not rotated by rotation of the first rotary member; a second magnetic field detecting element fixed to the non-rotary member, and located in such a manner as to receive a magnetic field from the ring magnet; a slide magnet for producing a magnetic field in a different direction from that of the magnetic field of the ring magnet in the second magnetic field detecting element; and a sliding mechanism configured to move the slide magnet toward or apart from the second magnetic field detecting element with the rotation of the first rotary member, characterised in that the second magnetic field detecting element is configured to be able to detect a magnetic field strength received from the ring magnet, and a magnetic field strength received from the slide magnet.