PURPOSE: To eliminate the generation of instability of the initial spring force due to an end turn part of a torque spring, and to accurately set a space for insertion and drawing of a torque pin in response to the required torque characteristic.

CONSTITUTION: A main spring 13a and an auxiliary spring 13b are arranged in series to each other in both sides of a spring receiver part 12b of a torque pin 12 so as to form a torque spring 13. The rear end of the torque spring 13 is received by a spring receiver 14. A pin adjuster 16 is passed through an adjusting screw hole 14a, which is formed in the spring receiver 14, freely to be moved in advance or retreat, and the tip of this pin adjuster 16 is faced to the rear end 12c of the torque pin 12 with a space (t) for insertion and drawing of the torque pin 12.