A driving state determining system in a vehicle recognizes an obstruction that may collide with the vehicle based on obtained various information. The system executes a plurality of danger determinations that have individual determination conditions, based on a relative distance and a relative speed with the obstruction to thereby comprehensively determine one of danger regions that the vehicle is situated in. The danger regions are classified depending on a danger degree. The system then outputs a determined result to relevant devices. Each of the relevant devices thereby determines operation by obtaining the comprehensively determined result outputted by the system. Consequently, the relevant devices can function more cooperatively and more effectively to lead to increase in safety than another system where each of relevant devices determines operation by individually collecting information.