A fixing structure includes a housing including a first hole, an input member including a second hole, and rotating relative to the housing, depending on input of rotational force, a torsion spring being biased so as to return, to a predetermined reference position, a position of the input member relative to the housing, and a fixing member inserted into the first hole and the second hole in a state where the input member is rotated against biasing force of the torsion spring from the reference position to a predetermined rotational position. The fixing member includes a first insertion portion including a part press-fitted into and fixed to the first hole, and a second insertion portion including a part inserted into the second hole, and fixes the input member at the predetermined rotational position.