Webbing retractor

A pinion of a pretensioner is provided at a side of a torsion shaft, which side is opposite a side connected integrally to a spool via a sleeve. A base lock of a lock mechanism is connected to the pinion. Due to the lock mechanism operating, a leg plate side end portion of the torsion shaft is locked. In this way, due to operation of the pretensioner, the pinion, which is connected to a rotating portion of a sleeve, also is locked by the locking mechanism. Therefore, a piston of the pretensioner is not lowered, and internal pressure of a cylinder does not affect deformation of the torsion shaft.