Abstract: An inertia locking mechanism of a vehicle occupant restraint belt retractor includes a blocking member that moves forwardly in response to frontal vehicle deceleration so as to block movement of the locking member of the mechanism back towards a nonlocking position after movement toward a locking position under the impetus of an inertia member. The blocking member has a lower end pivotally supported on the housing of the retractor about a transverse vehicle axis and extends upwardly between forward and rearward stops to an upper weighted portion that normally biases the blocking member rearwardly into engagement with the rearward stop. An actuating portion of the locking member normally engages the weighted portion of the blocking member and a blocking portion of the blocking member is located rearwardly of the actuating portion.