A refrigerator including a refrigerator main body having a refrigerating chamber therein, a cold air passage duct provided within the refrigerator main body and having a cold air passage therein to discharge the cold air into the refrigerating chamber, a control case attached to one surface of the cold air discharge duct and having a cold air discharge opening through which the cold air is discharged, and a knob provided between the cold air passage duct and the control case and attached to the control case to be reciprocally movable in one direction, the knob opening and closing at least part of the cold air discharge opening.