PRETENSIONER, RETRACTOR, AND SEAT BELT DEVICE

Provided are a pretensioner, a retractor, and a seat belt device in which strength and slidability of a rod-shaped power transmission member may both be achieved. A pretensioner 3 includes a ring gear 31 on which the spool 2 is rotatably disposed, and power transmission units 32 for transmitting power to the ring gear 31 in an emergency. The power transmission units 32 includes a rod-shaped power transmission member 32a for transmitting power to the ring gear 31 while being plastically deformed, a tip reinforcing member 32b disposed on a tip side of the power transmission member 32a, a pipe 32c for containing the power transmission member 32a, and a gas generator 32d disposed at an end of the pipe 32c. The tip reinforcing member 32b has higher strength than the power transmission member 32a.