A lock-type seat belt retractor including a ratchet mechanism, an inertia member which senses shock to the automobile, and a transmitting mechanism which transmits a movement of the inertia member to a pawl of the ratchet mechanism. The inertia member senses the shock by its relative motion to the transmitting mechanism. The transmitting mechanism includes a rod which moves in response to movement of the inertia member and pushes up a lever to raise the pawl. When the pawl engages with a tooth of a ratchet wheel, the seat belt is locked. The transmitting mechanism further includes a member which supports the rod and the inertia member. The support member swings relative to the automobile body so that this retractor can be locked reliably regardless of its angular position.