To reduce influence of external electric field noise, in a torque sensor for detecting torque, by using a pair of magnetic yokes made of a soft magnetic substance and a multipolar magnet.

Density of a magnetic flux generated by relative rotation of the multipolar magnet 22 fixed to a first steering shaft 14, and the pair of soft magnetic substance magnetic yokes 23 and 24 fixed to a second steering shaft 15, is detected by a Hall IC 30 via a pair of magnetic collecting rings 27 and 28 mutually facing an air gap 29. A correction Hall IC 44 is arranged at a position avoiding the air gap 29. An ECU 18 subtracts a correction value A1, based on output B1 of the correction Hall IC 44 from output E1 of the Hall IC 30. A computing element 47 of the ECU 18 arithmetically operates the torque, applied to the first and second steering shafts 14 and 15 based on a subtracted value E1-A1.