To provide a highly sensitive and highly accurate torque detecting device for power steering having the simple and small constitution.

A lower part 3 of an upper shaft 1 is housed in a housing part 4 formed on the upper end of a lower shaft 2, and strain gauges 9a and 9b are interposed between a projecting part 7 arranged in the lower part 3 and projecting parts 8a and 8b of the housing part 4. Voltage is outputted from the strain gauge 9a or 9b by pressing from the upper shaft 1 and the housing part 4 when rotating the upper shaft 1 by operating a handle, this voltage is transmitted to an electric circuit 12 via an antenna 11 from a transmitter 10, and a torque converted here is transmitted to a control unit. While, an optical sensor 15 combined with a light transmissive part 14 arranged in the peripheral circumferential direction of the housing part 4 detects a turning angle of the housing 4, and transmits a detecting result to the control unit via the electric circuit 12.