When an own vehicle waits to turn left or right, a vehicle data processing unit processes information of an oncoming vehicle based on data analyzed by data analyzing units. A support processing unit sets a blind angle rank according to a difficulty degree of recognizing a following vehicle due to the blind angle of a lead vehicle from the relationship in the vehicle body size between the lead and following vehicles based on the oncoming vehicle information, and sets the highest blind angle rank value as an oncoming straight-ahead vehicle rank flag. It also sets an evaluation rank according to a risk degree when the own vehicle turns left or right, based on the oncoming straight-ahead vehicle rank flag and an oncoming vehicle rank flag set according to the size of an oncoming vehicle waiting to turn left or right, and informs the driver of driving support information according to the evaluation rank.