User terminal device and luminance adujustment method thereof

The user terminal device is disclosed. The user terminal apparatus includes a display, a first sensor, second sensor and, detected by a first sensor for sensing the light which is provided in the rear irradiation of the user terminal device that detects the light that is provided in front of the user terminal device irradiation the basis of the front luminance and the illuminance detected by the second sensor back to a controller for adjusting the brightness of the display.