A system for authentication of a mobile terminal in which the mobile terminal transmits an authentication code to a server of a mobile service provider such that the mobile terminal can use a mobile communication service provided by the server, the system comprising: a tag for storing the authentication code and transmitting the authentication code to the mobile terminal using a first communication type; and the mobile terminal for receiving the authentication code using a second communication type using a substantially same frequency band as that of the first communication type and transmitting the received authentication code to the server of the mobile service provider using a predetermined third communication type, wherein the tag comprises a first storage for storing the authentication code, and a first communication unit for transmitting the authentication code to the mobile terminal using the first communication type, wherein the mobile terminal comprises a second communication unit for receiving the authentication code using the second communication type, a controller controllably transmitting the authentication code received by the second communication unit to the server of the mobile service provider, and a second storage for storing an application for authentication, and wherein the controller is adapted to drive the application to display a message requesting a user to approach the tag to the mobile terminal for authentication in a case the user purchases the mobile terminal and applies a power source to the mobile terminal, and is adapted to receive the authentication code stored in the first storage of the tag through the first communication unit and the second communication unit in a case the user approaches the tag to the mobile terminal, and wherein the mobile terminal is adapted to use the mobile communication service in a case the authentication has been completed. a tag for storing the authentication code and transmitting the authentication code to the mobile terminal using a first communication type; and the mobile terminal for receiving the authentication code using a second communication type using a substantially same frequency band as that of the first communication type and transmitting the received authentication code to the server of the mobile service provider using a predetermined third communication type, wherein the tag comprises a first storage for storing the authentication code, and a first communication unit for transmitting the authentication code to the mobile terminal using the first communication type, wherein the mobile terminal comprises a second communication unit for receiving the authentication code using the second communication type, a controller controllably transmitting the authentication code received by the second communication unit to the server of the mobile service provider, and a second storage for storing an application for authentication, and wherein the controller is adapted to drive the application to display a message requesting a user to approach the tag to the mobile terminal for authentication in a case the user purchases the mobile terminal and applies a power source to the mobile terminal, and is adapted to receive the authentication code stored in the first storage of the tag through the first communication unit and the second communication unit in a case the user approaches the tag to the mobile terminal, and wherein the mobile terminal is adapted to use the mobile communication service in a case the authentication has been completed.