SEAT BELT RETRACTOR

A seat belt retractor includes a housing including a pair of side walls facing each other, a winding drum configured to wind up a webbing, a locking base prevented from being rotated in the pull-out direction, in an emergency of a vehicle, an impact energy absorbing member including a first end side coupled to the winding drum and a second end side coupled to the locking base, the impact energy absorbing member connecting the winding drum and the locking base so as to be integrally rotatable, in a normal state, at least one impact energy absorbing wire housed in at least one slot that is provided in the winding drum, and a stopper member configured to define an allowable amount of relative rotation between the winding drum and the locking base in a case where the impact energy absorbing member absorbs the impact energy.