Webbing insertion member

A webbing insertion member in which a webbing hardly shifts within an opening during the operation of a pretensioner mechanism. The insertion member includes a bearing portion and an opening through which the webbing passes. In order to prevent the shifting of the webbing in the longitudinal direction of the opening, a pair of webbing guides are formed to project from a surface of the bearing portion on a rear side of the insertion member. The webbing is suspended on the bearing portion and passes between the guides. Therefore, the guides confront with the left and right sides of the webbing thereby preventing the webbing from shifting in the lateral direction.