Seat belt retractor

A seat belt retractor comprising:

• a housing including a pair of side walls facing each other;
• a winding drum configured to wind up a webbing, the winding drum being housed between the pair of side walls so as to be rotatable in a winding direction and a pull-out direction of the webbing;
• a lock member provided at a first end portion, of the winding drum, located on one side in an axial direction of the winding drum, the lock member being configured to be movable between:
• an engagement position in which rotation of the winding drum in the pull-out direction is prevented by the lock member being engaged with the housing or a member attached to the housing;
• and a non-engagement position in which the rotation of the winding drum in the pull-out direction is allowed, the lock member being moved to the engagement position in an emergency of a vehicle;
• a biasing member including:
• one end portion attached to the first end portion of the winding drum;
• an other end portion attached to the lock member;
• and a connecting portion connecting the one end portion and the other end portion, the biasing member being configured to bias the lock member to maintain the lock member at the non-engagement position;
• a shaft member attached to the first end portion of the winding drum, the shaft member including a shaft portion coaxial with the winding drum;
• and
• a cover member attached to the housing, the cover member rotatably supporting the shaft portion of the shaft member,
• wherein the shaft member includes an arm extending, from the shaft portion, outward in a radial direction,
• the arm is configured to be able to come into contact with the connecting portion of the biasing member from a side opposite to the winding drum,
• wherein the shaft member includes a hook extending from a distal end of the arm to the other side in the axial direction of the winding drum, and
• the first end portion of the winding drum is provided with an engagement hole with which the hook is engaged.