PURPOSE: To simplify a structure and to reduce cost by providing a locking means for moving a locking pawl to a starting or non-starting position by using a cam member according to rotation of an unwinding or winding direction of a spindle to hold the member at the non-starting or starting position.

CONSTITUTION: After a belt is drawn from a retractor 10, a cam member 106 pivotally secures a starting lever 110 to a starting position. The lever 110 maintains a lock-up lever 98 to an engaging position during rotation of a belt winding direction of the spindle 22. Thereafter, the member 106 pivotally secures the lever 110 to a non-starting position. A locking spring 164 has a first part 120 for engaging with a locking arm 166 when the lever 110 is disposed at the non-starting position and a second part 172 for engaging with the arm 166 when it is disposed at the starting position.