An engagement-side flange portion, one of a pair of flange portions on the respective axial ends of a webbing-take-up portion of a take-up drum, is positioned to face engagement teeth and includes a projecting portion formed to project radially outward from its peripheral edge that faces a pawl when the pawl moves to reach engagement position with the engagement teeth. Outer peripheral diameter of engagement-side flange portion is smaller than inner peripheral diameter defined with tip ends of engagement teeth. Maximum outer peripheral dimension formed by the projecting portion and engagement-side flange portion is larger than inner peripheral diameter defined with tip ends of engagement teeth. In a state where the take-up drum is attached to a housing, the projecting portion projects radially outward over inner peripheral diameter defined with tip ends of engagement teeth that is located at axially outward side of the projecting portion.