A refrigerator comprising: a case having a storage chamber provided therein; a lighting device to light an inner space of the storage chamber; a first door that is rotatably coupled to the case to open and close the storage chamber and has a hole penetrating the door, the first door comprising an auxiliary storage chamber provided therein; a second door that is rotatable with respect to the first door to open and close the auxiliary storage chamber and has a hole penetrating the second door, the second door comprising: a front panel configured to form a front appearance of the door, the front panel formed of a transparent material; a variable transparency film deposited on the back surface of the front panel, wherein the variable transparency film is configured to be transparent, when power is supplied thereto; and an insulation panel formed of a transparent material and provided in the hole and behind the front panel; wherein the refrigerator further comprises: a proximity sensor that is provided in a portion of the second door and is configured to sense a user's approaching; and a control unit configured to control the lighting device to make visible to the user an inside of the auxiliary storage chamber through the hole of the second door due to transmitting of the light inside the auxiliary storage chamber through the insulation panel and the front panel, wherein the control unit is configured to control a power supply unit to operate the variable transparency film and the lighting device simultaneously based on the sensing signal of the proximity sensor, wherein the control unit is configured to determine change in the intensity of the sensing signal transmitted to the proximity sensor and wherein when the user is getting closer to the door, the power supply unit increases the power supplied to the variable transparency film and the lighting device so that the transparency level of the variable transparency film is gradually getting higher in an opaque state and a brightness level of the lighting device is getting higher. a case having a storage chamber provided therein; a lighting device to light an inner space of the storage chamber; a first door that is rotatably coupled to the case to open and close the storage chamber and has a hole penetrating the door, the first door comprising an auxiliary storage chamber provided therein; a second door that is rotatable with respect to the first door to open and close the auxiliary storage chamber and has a hole penetrating the second door, the second door comprising: a front panel configured to form a front appearance of the door, the front panel formed of a transparent material; a variable transparency film deposited on the back surface of the front panel, wherein the variable transparency film is configured to be transparent, when power is supplied thereto; and an insulation panel formed of a transparent material and provided in the hole and behind the front panel; a front panel configured to form a front appearance of the door, the front panel formed of a transparent material; a variable transparency film deposited on the back surface of the front panel, wherein the variable transparency film is configured to be transparent, when power is supplied thereto; and an insulation panel formed of a transparent material and provided in the hole and behind the front panel; wherein the refrigerator further comprises: a proximity sensor that is provided in a portion of the second door and is configured to sense a user's approaching; and a control unit configured to control the lighting device to make visible to the user an inside of the auxiliary storage chamber through the hole of the second door due to transmitting of the light inside the auxiliary storage chamber through the insulation panel and the front panel, wherein the control unit is configured to control a power supply unit to operate the variable transparency film and the lighting device simultaneously based on the sensing signal of the proximity sensor, wherein the control unit is configured to determine change in the intensity of the sensing signal transmitted to the proximity sensor and wherein when the user is getting closer to the door, the power supply unit increases the power supplied to the variable transparency film and the lighting device so that the transparency level of the variable transparency film is gradually getting higher in an opaque state and a brightness level of the lighting device is getting higher. a proximity sensor that is provided in a portion of the second door and is configured to sense a user's approaching; and a control unit configured to control the lighting device to make visible to the user an inside of the auxiliary storage chamber through the hole of the second door due to transmitting of the light inside the auxiliary storage chamber through the insulation panel and the front panel, wherein the control unit is configured to control a power supply unit to operate the variable transparency film and the lighting device simultaneously based on the sensing signal of the proximity sensor, wherein the control unit is configured to determine change in the intensity of the sensing signal transmitted to the proximity sensor and wherein when the user is getting closer to the door, the power supply unit increases the power supplied to the variable transparency film and the lighting device so that the transparency level of the variable transparency film is gradually getting higher in an opaque state and a brightness level of the lighting device is getting higher.