A method of discriminating an approaching vehicle was devised for the purpose of constructing a visual driver assistance system at an intersection using a monocular camera. When a monocular camera is used, it is basically difficult to acquire distance information, so vehicle detection and discrimination of approaching vehicles without the use of distance information are associated issues. In this research, the presence of a vehicle at an intersection is detected by classifying the region on the image that has the shape of the vehicle, and the degree of the vehicle approach is discriminated by comparing the motion vector of the vehicle with the subject vehicle's direction of movement. By performing a test using this method, it was confirmed that it is possible to discriminate approaching vehicles.