To record a correct room entry/exit history in response to the action of a user.

A room entry/exit management system includes: an antenna 2a for detecting room entry installed outside a gateway in a management object facility; an antenna 2b for detecting room exit installed in the gateway; a tag reader 4 that compares, after one of the antenna 2a for detecting room entry and the antenna 2b for detecting room exit reads identification information from a tag 6 and when the other reads the identification information from the tag 6, identification information read by the two antennas to determine that a user identified by the identification information passes through the gateway to enter/exit the room when the identification information matches; and a room entry/exit management device 1 that records the room entry/exit history information of the user when a user identified by the identification information is determined to enter/exit the room.