Disclosed is a load limiter mounted within a cylindrical spool on which a webbing is wound to constrain a load applied to the webbing from exceeding a preset load, the load limiter including: a first torsion bar inserted into a hollow portion formed at a center of the spool and one end of which is coupled to one end of the spool; and a second torsion bar one end of which is connected to an opposite end of the first torsion bar to be inserted into the hollow portion of the spool together with the first torsion bar and an opposite end of which is coupled to a locker installed at an opposite end of the spool, wherein the torsion bar is configured such that a torsion load limit of the first torsion bar is smaller than a torsion load limit of the second torsion bar.