A Near Field Communication device that performs NFC with a reader/writer, said NFC device comprising: an antenna unit configured to receive radio waves from the reader/writer by NFC; a first power source unit configured to generate power from the radio waves received by said antenna unit; a second power source unit that is a drive power source different from said first power source unit and that is capable of being powered ON or OFF; a power-supply state holding unit configured to hold power-supply state information indicating a power-supply state of said second power source unit; an NFC unit configured to transmit the power-supply state information recorded on said power-supply state holding unit to the reader/writer via said antenna unit by using NFC; a power source switch unit configured to switch between said first power source unit and said second power source unit according to the power-supply state of said second power source unit, in order to supply power to activate at least said NFC unit and said power-supply state holding unit; and a system control unit configured to receive power from said second power source unit and rewrite the power-supply state information recorded on said power-supply state holding unit, wherein said power source switch unit is configured to: (i) switch from said first power source unit to said second power source unit in order to supply power to said NFC unit and said power-supply state holding unit, when said second power source unit supplies power to said system control unit; and (ii) switch from said second power source unit to said first power source unit in order to supply power to said NFC unit and said power-supply state holding unit, when said second power source unit does not supply power to said system control unit, and said system control unit is configured to: (i) rewrite the power-supply state information held on said power-supply state holding unit to indicate that said second power source unit is powered ON, when said second power source unit is powered ON from OFF; and (ii) rewrite the power-supply state information held on said power-supply state holding unit to indicate that said second power source unit is powered OFF, and then power said second power source unit OFF from ON. an antenna unit configured to receive radio waves from the reader/writer by NFC; a first power source unit configured to generate power from the radio waves received by said antenna unit; a second power source unit that is a drive power source different from said first power source unit and that is capable of being powered ON or OFF; a power-supply state holding unit configured to hold power-supply state information indicating a power-supply state of said second power source unit; an NFC unit configured to transmit the power-supply state information recorded on said power-supply state holding unit to the reader/writer via said antenna unit by using NFC; a power source switch unit configured to switch between said first power source unit and said second power source unit according to the power-supply state of said second power source unit, in order to supply power to activate at least said NFC unit and said power-supply state holding unit; and a system control unit configured to receive power from said second power source unit and rewrite the power-supply state information recorded on said power-supply state holding unit, wherein said power source switch unit is configured to: (i) switch from said first power source unit to said second power source unit in order to supply power to said NFC unit and said power-supply state holding unit, when said second power source unit supplies power to said system control unit; and (ii) switch from said second power source unit to said first power source unit in order to supply power to said NFC unit and said power-supply state holding unit, when said second power source unit does not supply power to said system control unit, and said system control unit is configured to: (i) rewrite the power-supply state information held on said power-supply state holding unit to indicate that said second power source unit is powered ON, when said second power source unit is powered ON from OFF; and (ii) rewrite the power-supply state information held on said power-supply state holding unit to indicate that said second power source unit is powered OFF, and then power said second power source unit OFF from ON.