A refrigerator comprising: a cabinet having a storage compartment; a main door mounted at the cabinet by a hinge and having an access opening; an auxiliary storage compartment provided on the main door and accessible through the access opening of the main door; a sub door mounted on the main door and configured to open and close the access opening; a handle attached to the sub door; a catching protrusion provided at a coupling groove formed at the main door; a hook member pivotably mounted at the sub door and protruding from a surface of the sub door and configured to selectively engage with the catching protrusion; a lock control device mounted in the sub door and configured to unlock the locking of the catching protrusion and the hook member; wherein the main door and the sub door are opened simultaneously while being coupled to each other as a result of the handle being pulled, characterized in that the handle is pivotably attached to the sub door and configured to move rearward, wherein the lock control device is configured to unlock the locking of the catching protrusion and the hook member as a result of the handle being moved rearward; and in that the refrigerator further comprises: a repulsion member disposed at the rear side of the sub door and configured to prevent the hook member from being caught by the catching protrusion again when the user releases his/her hand after the user pushes the handle; wherein the lock control device comprises: a push rod configured to convert horizontal motion of the handle into vertical longitudinal motion and transmit the converted vertical longitudinal motion; and a pivoting member pivotably mounted together with the hook member and configured to vertically pivot as a result of the vertical longitudinal motion of the push rod, wherein the sub door is separated from the main door and only the sub door is opened as a result of the handle being pushed. a cabinet having a storage compartment; a main door mounted at the cabinet by a hinge and having an access opening; an auxiliary storage compartment provided on the main door and accessible through the access opening of the main door; a sub door mounted on the main door and configured to open and close the access opening; a handle attached to the sub door; a catching protrusion provided at a coupling groove formed at the main door; a hook member pivotably mounted at the sub door and protruding from a surface of the sub door and configured to selectively engage with the catching protrusion; a lock control device mounted in the sub door and configured to unlock the locking of the catching protrusion and the hook member; wherein the main door and the sub door are opened simultaneously while being coupled to each other as a result of the handle being pulled, characterized in that the handle is pivotably attached to the sub door and configured to move rearward, wherein the lock control device is configured to unlock the locking of the catching protrusion and the hook member as a result of the handle being moved rearward; and in that the refrigerator further comprises: a repulsion member disposed at the rear side of the sub door and configured to prevent the hook member from being caught by the catching protrusion again when the user releases his/her hand after the user pushes the handle; wherein the lock control device comprises: a push rod configured to convert horizontal motion of the handle into vertical longitudinal motion and transmit the converted vertical longitudinal motion; and a pivoting member pivotably mounted together with the hook member and configured to vertically pivot as a result of the vertical longitudinal motion of the push rod, wherein the sub door is separated from the main door and only the sub door is opened as a result of the handle being pushed.