A license server 1 comprises: a license table for managing licenses purchased by users; a communication control section 20 for transmitting/receiving data through a communications network 3; an authentication control section 22 for performs authentication processing for a terminal 2; an encryption/decryption control section 21 for encrypting/decrypting communications with the terminal 2; an issued temporary license information table 13 for storing information on issued temporary licenses; and a return control section 24 for returning a temporary license and then deleting the information on the temporary license stored in the issued temporary license information table 13.