In a webbing take-up device, side faces of press-fit holes in a pinion are inclined in directions toward the outside of the press-fit holes on progression toward the right. Press-fit portions of a torsion shaft are press-fit into the press-fit holes from the right such that an interference force between the press-fit portions and the side faces of the press-fit holes increases on progression toward the left. This enables the press-fit portions to be effectively retained in the press-fit holes.