A device includes: a short-range communicator which is configured to communicate with at least one mobile terminal by a short-range communication method; and a controller which is configured to determine whether a mobile terminal targeted for approaching is a registered mobile terminal if it is detected that the mobile terminal approaches the device, and controls the short-range communicator to receive the first authentication information corresponding to the device from the approached mobile terminal if the approached mobile terminal is determined as the registered mobile terminal, and authenticate a user of the device through the received first authentication information. With this, a user can be authenticated by a simple method of making the mobile terminal approach the device without inputting his/her authentication information, thereby improving user's convenience and strengthening security effect.