A refrigerator includes an inner case forming a storage compartment therein, the inner case including an inner wall surrounding the storage compartment; an outer case coupled to an outer side of the inner case; a foamed insulation material disposed between the inner case and the outer case; a storage container configured to be slidably inserted into and withdrawn from the storage compartment; a rail unit disposed inside the storage compartment, the rail unit being configured to guide a movement of the storage container, the rail unit including a coupling protrusion that is coupled to the inner wall; an insertion groove formed on the inner wall to allow the coupling protrusion to insert therein; and a coupling groove formed on the inner wall so that the rail unit coupled to the insertion groove fixes to the inner wall.