To provide a room entrance authentication system which, while based on the plural-person authentication, can also set a user allowed to pass alone ignoring this authentication, to improve its convenience and facilitates the management of a room entrance method per individual/room unit.

In the room entrance authentication system with an authenticating function of a plurality of persons, as a room entrance condition, the number of authenticated persons to determine the number of persons required to enter into a room can be set in room data, and a room entrance right indicating whether the person has a right to enter into the room or not and also a single-person room entrance privilege indicating the right to enter into the room alone, ignoring the room entrance condition even when authentication is allowed to the plurality of persons set in the room data, both rights can be set in individual ID data.