Patent ID: 8287049

Claim:
A pretensioner that exerts a pull-in force on a seat belt including at least a lap belt among a shoulder belt and the lap belt when a vehicle undergoes an impact, the pretensioner comprising: a wire that is connected at one end to the seat belt; a piston that is connected to the other end of the wire; a cylinder that houses the piston slidably; a housing that allows the wire to run therethrough and holds the cylinder; a gas-supplying device that supplies gas into the cylinder through an interior of the housing in order to operate the piston in a direction in which the wire is pulled in; and an apertured member that is arranged in the housing so as to cover at least a gas-supplying device side of a peripheral surface of the wire, and that has a plurality of through-holes and thereby is able to diffuse the gas, wherein the apertured member has a seal portion that seals a gap between the wire and an inner wall surface of the housing, and a protecting portion that extends from the seal portion to a cylinder side and covers the peripheral surface of the wire, the seal portion and the protecting portions being formed integrally; and the plurality of through-holes is provided in the protecting portion.