PURPOSE: To automatically traffic signal neglect by detecting a signal neglecting vehicle according to the travel position and travel speed of the vehicle detected by a vehicle movement measuring means and the signal state of a signal light detected by a signal state detecting means.

CONSTITUTION: A traffic signal controller 6 outputs the illumination control signal for the signal light 5 according to internal data or data from a center device and this signal is inputted even to the signal state detection part 22 of a signal neglecting vehicle measurement part 22. The signal state detection part 22 detects the current signal state from the illumination control signal for the signal light 5 and sends information on the signal state to a vehicle movement measurement part 21. The vehicle movement measurement part 21 links information on the signal state of the signal light 5 with the vehicle-by- vehicle distances from the intersection and travel speeds records them as histories by the vehicles. The signal neglecting vehicle measurement part 2 decides whether or not the traveling vehicle neglects the signal according to the signal state of the signal light and the information on the distances from the intersection and travel speeds.