To provide a torque measuring apparatus which enables miniaturization and a lower cost with a simple structure.

In the torsion quantity measuring apparatus, which has an input side rotor 2 and an output side rotor 4 arranged free to rotate circumferentially and detects a relative torsion quantity between the input side rotor 2 and the output side rotor 4, an input side stator 1 is installed at a position facing the input side rotor 2 in the circumferential direction thereof at a prescribed interval and an output side stator 3 at a position circumferentially facing the output side rotor 4 at a prescribed interval. The input side stator 1 and the output side stator 3 have respectively an exciting winding and output windings 5 and 6, and the output winding of the input side stator 1 and the output winding of the output side stator 3 are interconnected.