A refrigerator comprising: a cabinet having a storage compartment; a main door mounted on 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 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 handle horizontally pivotably mounted at a vertical pivoting shaft mounted at the sub door and configured to be pushed rearward; and a lock control device mounted in the sub door and configured to unlock the locking of the catching protrusion and the hook member as a result of the handle being pushed rearward, wherein the handle is configured to open the main door and the sub door simultaneously as a result of the handle being pulled, characterized in that, the hook member is mounted at a middle height of the sub door and the handle is mounted at a lower end of the sub door and in that the lock control device comprises: a push rod configured to convert horizontal pivoting 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. a cabinet having a storage compartment; a main door mounted on 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 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 handle horizontally pivotably mounted at a vertical pivoting shaft mounted at the sub door and configured to be pushed rearward; and a lock control device mounted in the sub door and configured to unlock the locking of the catching protrusion and the hook member as a result of the handle being pushed rearward, wherein the handle is configured to open the main door and the sub door simultaneously as a result of the handle being pulled, characterized in that, the hook member is mounted at a middle height of the sub door and the handle is mounted at a lower end of the sub door and in that the lock control device comprises: a push rod configured to convert horizontal pivoting 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. a push rod configured to convert horizontal pivoting 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.