To provide an entrance and exit gate ID card management system capable of integrally performing entrance and exit gate state management and entrance and exit ID card reissue management in a plurality of facilities, and to provide its method.

The entrance and exit gate ID card management system 1 includes: an entrance and exit gate ID card integration management device 10; and the plurality of entrance and exit gate ID card management devices 20, 30 which are mutually connected to the entrance and exit gate ID card integration management device 10 via a communication line 40. The entrance and exit gate ID card integration management device 10 includes an abnormality determining part 14 for reading data about an entrance and exit gate state stored in an entrance and exit gate state database 17, checking whether or not abnormal entrance and exit or reissue is performed as regards a specific entrance and exit ID card, and transmitting the abnormal entrance and exit or the reissue to the entrance and exit gate ID card management devices 20, 30 arranged in the facility which issues the entrance and exit gate ID card among the plurality of facilities when the entrance and exit gate ID card with the abnormal entrance and exit or reissue is found.