Visitor authentication system, and visitor authentication method

Visitor authentication system 1, the IC card 8 visitor 7 to visit visited 3 possessed, a server device 20 that stores a timed information (collation information 60) which has an IC card writing device 16, installed in the visited 3, and a visited system 10 which is communicatively connected to the server device 20 together with the IC card reading and writing device 16. Visitor authentication system 1, prior to the visit to the visited 3 visitors 7, writing a timed information to the IC card 8. Visitor authentication system 1, when a visit to the visited 3 visitors 7, the information read from the IC card 8 set in the writing device 16 IC card reader, a timed server device 20 is stored to authenticate the visitors 7 by collating the information. Visitor authentication system 1, when the collation for the valid period information outside the of the time-limited information server apparatus 20 stores to be excluded from the collation.