A passenger protection system includes acceleration sensors as well as a passenger protection ECU. At least one acceleration sensor is provided on one of the width-direction sides of the vehicle and at least one accelerator sensor is provided on the other width-direction side of the vehicle. Based on signals generated by the acceleration sensors the passenger protection ECU determines occurrence of a collision, and drives passenger protection apparatus accordingly. In the event of a collision, the passenger protection ECU performs an AND operation on a signal from the acceleration sensor on the colliding one of the width-direction sides of the vehicle, and a signal from the acceleration sensor on the other width-direction side not experiencing the collision, to drive the passenger protection apparatus.