To provide the gate passage management system which accurately detects vehicles and prevents illegal entrance or exiting, robbery, etc.

This management system picks up images of peripheries of car gate devices 103 and 104 controlling the passage of vehicles by cameras 101 and 102 and extracts an object by generating and processing difference images between the picked-up images and previously stored images. Then this system is equipped with a vehicle passage decision processor 107 which places the car gate devices 103 and 104, a VCR 110, and an alarm output device 108 in operation according to the extracted states of the object and car gate devices 103 and 104 and predetermined conditions.