A preloader adapted to forcibly pull a webbing in a taking-up direction when the vehicle suddenly decelerates, so as to allow the webbing to be applied closely around an occupant. A clamp member for clamping the webbing is provided to prevent a subsequent tight winding of the webbing. The clamp member is constantly urged in a webbing-clamping direction by an urging member, and is normally held in a position spaced apart from the webbing against an urging force of the urging member. As the holding is canceled after the forcible taking up of the webbing, the clamp member is capable of clamping the webbing.