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 being prevented from being rotated in the pull-out direction, in an emergency of a vehicle, an impact energy absorbing member connecting the winding drum and the locking base so as to be integrally rotatable in a normal state, an impact energy absorbing wire housed in a slot provided in the winding drum so as to form an opening in the first end surface of the winding drum, a ring provided integrally with or separately from the locking base, and a stopper member being 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.