Patent ID: 8010256

Claim:
A collision detector which detects a collision of a vehicle to activate an occupant protector unit, comprising: a plurality of acceleration sensors provided at different positions in the vehicle to detect acceleration of the vehicle; a collision determiner unit which determines whether or not a variation in the acceleration detected by each of the acceleration sensors is caused by a collision of the vehicle; a final determiner unit which activates the occupant protector unit when the collision determiner unit determines that all of variations in the acceleration detected by each acceleration sensor are caused by a collision of the vehicle; an acceleration determiner unit which determines whether or not the acceleration detected by each acceleration sensor is equal to or over a predetermined threshold; and a speed variation determiner unit which determines whether or not a speed variation of the vehicle coincides with a pre-stored speed variation which occurs at a collision, when the acceleration determiner unit determines that the acceleration is equal to or over the predetermined threshold, wherein when receiving a same acceleration, at least one of the acceleration sensors is set to be higher in output level than the other acceleration sensor(s).