A vehicle passenger restraint system comprises a shoulder belt for restraining a passenger to a vehicle seat. The shoulder belt extends diagonally from a shoulder area on one side of the passenger to a waist area on the opposite side of the passenger and has a belt inflatable part configured to be inflated with a fluid upon a collision of the vehicle is detected. The belt inflatable part is provided with a head restraining part configured to deploy in the forward direction of the vehicle as the belt inflatable part inflates to receive the passenger's head. When the belt inflatable part inflates, tension is generated in the shoulder belt and the tension increases the force with which the passenger is restrained. Simultaneously, the head restraining part is inflated to receive the passenger's head and to prevent the passenger's head from contacting a frontward vehicle part.