To provide a torque detection device capable of detecting a torque without using an angle of torsion.

A motor 21 for torque detection for imparting an additional torque to an upper side part 2a of a steering shaft 2 is provided. An angle sensor 24 detects a rotation angle a of the upper side part 2a, and an angle sensor 25 detects a rotation angle b of a pinion 8. A motor control part 23 for torque detection performs driving control of the motor 21 for torque detection so that a difference between the rotation angles a, b becomes zero. A current sensor 26 detects a current Id flowing in the motor 21 for torque detection. A torque calculation part 27 determines a steering torque T working on the steering shaft 2 based on the detected current Id. The determined steering torque T is used when determining a steering auxiliary force generated from a steering auxiliary motor 11.