The invention provides a seatbelt retractor comprising at least: a spool for taking up a seatbelt, a lock mechanism having a locking member whereby rotation in the direction of extracting the seatbelt is obstructed in the event of an emergency, a torsion bar rotatably linking the spool and the locking member, and capable of being deformed by twisting and a seatbelt load restricting mechanism for restricting the load placed upon the seatbelt. The torsion bar deforms by twisting at the time that the rotation of the locking member in the direction of the seatbelt being extracted is obstructed. The spool rotates relative to the extraction direction of the seatbelt. The restriction load properties of the seatbelt load restricting mechanism comprise a relatively small restriction load due to twisting deformation of the torsion bar alone, and a relatively great restriction load made up of a restriction load due to twisting deformation of the torsion bar and a restriction load due to another member. The relatively great restriction load is set to have properties which change in a plurality of steps.