A torque sensor for electrically detecting torque, such as the torque of an automobile engine, wherein a strain disk is provided in the path of torque transmission and the torque is magnetically detected in terms of the magnetostriction generated in the strain disk. The torque sensor comprises a magnetic rotating disk and a magnetic sensor disposed in the vicinity of and opposed to the strain disk. The magnetic sensor comprises a detection coil and an excitation coil oriented perpendicularly to each other with the excitation coil ordinarily being disposed outside of the detection coil. Supplying alternating current to the excitation coil causes an alternating field to be produced within the strain disk and the configuration of this alternating magnetic field is varied by the anisotropy of the strain caused within the strain disk by the transmitted torque. The variation in the configuration of the alternating magnetic field is noncontactingly detected by the detection coil, which outputs a corresponding electrical signal from which the torque can be determined with high accuracy.