A support processor performs driving support processing of outputting a warning when it is judged that there is a possibility of collision between a subject vehicle and another vehicle based on subject vehicle information acquired by a subject vehicle information acquirer and another vehicle information acquired by an another vehicle information acquirer. A subject vehicle information predictor predicts an arrival time required until a subject vehicle arrives at an intersection based on subject vehicle information. A preceding vehicle information predictor predicts the position of a preceding vehicle at the time when a predicted arrival time elapses, based on preceding vehicle information acquired by a preceding vehicle information acquirer. A support execution determiner determines whether to permit or forbid the support processor to perform driving support processing according to a predicted position of a preceding vehicle.