A communication apparatus comprising: an interface unit adapted to read out identification information regarding a communication carrier from a storage medium in which the identification information is stored; a communicating unit (122, 123) adapted to decide the communication carrier based on the identification information read out by the interface unit and to make communication by using the decided communication carrier; an authenticating unit adapted to make an authentication by using the identification information read out by the interface unit; a control unit adapted to enable a communicating operation by the communicating unit (122, 123) according to a success in the authentication by the authenticating unit; a memory adapted to store fonts of languages of a plurality of countries; and a display control unit adapted to allow an authenticating display screen for making the authentication to be displayed onto a display apparatus, wherein the display control unit is adapted to decide a display language based on the identification information read out by the interface unit and to allow the authenticating display screen to be displayed by using the font of the decided display language among the fonts stored in the memory; wherein if the font of the display language decided based on the identification information is not stored in the memory, the display control unit is adapted to control the interface unit so as to read out the information of the font from the storage medium and to allow the authenticating display screen to be displayed by using the read-out font; and wherein the storage medium is a SIM card. an interface unit adapted to read out identification information regarding a communication carrier from a storage medium in which the identification information is stored; a communicating unit (122, 123) adapted to decide the communication carrier based on the identification information read out by the interface unit and to make communication by using the decided communication carrier; an authenticating unit adapted to make an authentication by using the identification information read out by the interface unit; a control unit adapted to enable a communicating operation by the communicating unit (122, 123) according to a success in the authentication by the authenticating unit; a memory adapted to store fonts of languages of a plurality of countries; and a display control unit adapted to allow an authenticating display screen for making the authentication to be displayed onto a display apparatus, wherein the display control unit is adapted to decide a display language based on the identification information read out by the interface unit and to allow the authenticating display screen to be displayed by using the font of the decided display language among the fonts stored in the memory; wherein if the font of the display language decided based on the identification information is not stored in the memory, the display control unit is adapted to control the interface unit so as to read out the information of the font from the storage medium and to allow the authenticating display screen to be displayed by using the read-out font; and wherein the storage medium is a SIM card.