To construct a bracket for supporting one end of a torsion bar with a torque adjusting mechanism to serve as the stationary side without causing enlargement and complication of the construction.

A torque adjusting mechanism for a torsion bar 4 is structure so that its one end 4a is supported on the bracket 1A side in the condition that a twist angle is given to the torsion bar 4 while the other end is supported on the hinge arm side. An attachment 10 equipped with a plurality of engaging grooves 13 and 14 engage the end 4a of the torsion bar 4 selectively is installed removably on the bracket 1A, and the twist angle of the torsion bar 4 is adjusted through selection of the engaging grooves 13/14 in the attachment 10. This establishes adjustability for the twist angle of the torsion bar 4 only through selection of the engaging grooves 13/14 in the attachment 10.