The present invention aims at providing a contactless card that enables a reader/writer to identify which card such reader/writer is communicating with in a set of card identification processes and that improves the possibility of protecting the cardholder's privacy. Contactless card (200) includes: power detection unit (203); random number ID generation unit (210) that determines an identifier that identifies card (200), every time power detection unit (203) detects that electric power has been supplied; ID storage unit (2081) that holds the determined identifier; sending/receiving circuit (204) that receives a command requesting that the identifier that identifies card (200) should be sent to reader/writer (100), and sending/receiving circuit (204) sends, to reader/writer (100), the determined identifier in the case where the received command is a first-received command, and the held identifier in the case where the received command is a second- or later-received command.