TORQUE SENSOR

PROBLEM TO BE SOLVED: To provide a torque sensor which can sense contact failures even if a torque detection coil and a temperature compensation coil are singlet systems, respectively. SOLUTION: Torque is detected based on a change in impedance occurring on a coil 12 according to torque to be detected. The torque sensor includes means 11, 21 for making constant current flow to coils 12, 22; AC detection means 13, 15, 23, 25 for detecting alternate current contained in output voltage of the coils 12, 22; DC detection means 17, 27 for detecting direct current contained in output voltage of the coils 12, 22; and means 18, 28, 35, 38 for detecting abnormality based on the direct current detected by the DC detection means 17, 27.