The present invention relates to a mobile terminal capable of a new type of user input, comprising: a backside input unit including a plurality of buttons and exposed to the backside of the mobile terminal; a memory for storing relationships between combinations of the plurality of buttons and control instructions of the mobile terminal and biometric information; a sensor unit, arranged on the backside of the mobile terminal and adjacent to the backside input unit, for sensing a user's bio signal; and a control unit for, upon receiving a user input in accordance with a particular combination of the plurality of buttons, controlling the sensor unit to sense the user's bio signal, and authenticating the user using the sensed bio signal and the stored biometric information.