To provide a security system and a security method capable of securing the security to the network.

The security system comprises: an IC tag 12A capable of reading and writing data by communication; a sensitive device 11 placed in an A facility and writing specific data to the IC tag 12A when the IC tag 12A goes away from the A facility; a sensitive device 31 placed in a B facility and reading data from the IC tag 12A when the IC tag 12A reaches the B facility; a switching device 15 for switching enabled/disabled condition of a corporate network 22 in the B facility; a control device 13 and a personal computer 14 for collating the data written to the IC tag 12A by the sensitive device 11 with the data read out from the IC tag 12A by the sensitive device 31 to control the switching device 15 when the two data are coincident, thereby enabling the corporate network 22.