A refrigerator comprising: an outer case formed in a box shape, defining an exterior of the refrigerator; and an inner case, disposed inside the outer case, providing a storage space for storing food items, the inner case including: an upper surface portion; two side surface portions; a rear surface portion; and a lower surface portion, the refrigerator further comprising a metal plate attached to an inner surface of the inner case, the metal plate including two side plates which are disposed inside the inner case, wherein the inner case includes a recessed portion formed at each of the two side surface portions, wherein the recessed portion is a portion of each of the two side surface portions that is bent outward at a position spaced apart from a front end thereof and then bent backward again, so that a respective one of the two side plates can be inserted therein, wherein the side plate includes: a second surface which shields an inner surface of the side surface portion; and a second front end portion which is bent backward from a front end of the second surface to be parallel to the second surface, characterized in that the side plate being inserted in the recessed portion, an outer surface of the second front end portion is in contact with an inner surface of the recessed portion, wherein the recessed portion is recessed in a depth corresponding to a width between the second front end portion and the second surface, wherein the side surface portion has a third coupling opening formed therein; wherein the side plate has a third coupling rib protruding from a front end thereof, to be inserted in the third coupling opening, wherein the third coupling rib includes: a third protruding portion protruding outward from an end of the second front end portion of the side plate; and a third bending portion (321b bent upward from the third protruding portion, wherein, the side plate being coupled with the inner case, the third protruding portion is inserted in the third coupling opening. an outer case formed in a box shape, defining an exterior of the refrigerator; and an inner case, disposed inside the outer case, providing a storage space for storing food items, the inner case including: an upper surface portion; two side surface portions; a rear surface portion; and a lower surface portion, an upper surface portion; two side surface portions; a rear surface portion; and a lower surface portion, the refrigerator further comprising a metal plate attached to an inner surface of the inner case, the metal plate including two side plates which are disposed inside the inner case, wherein the inner case includes a recessed portion formed at each of the two side surface portions, wherein the recessed portion is a portion of each of the two side surface portions that is bent outward at a position spaced apart from a front end thereof and then bent backward again, so that a respective one of the two side plates can be inserted therein, wherein the side plate includes: a second surface which shields an inner surface of the side surface portion; and a second front end portion which is bent backward from a front end of the second surface to be parallel to the second surface, characterized in that the side plate being inserted in the recessed portion, an outer surface of the second front end portion is in contact with an inner surface of the recessed portion, a second surface which shields an inner surface of the side surface portion; and a second front end portion which is bent backward from a front end of the second surface to be parallel to the second surface, characterized in that wherein the recessed portion is recessed in a depth corresponding to a width between the second front end portion and the second surface, wherein the side surface portion has a third coupling opening formed therein; wherein the side plate has a third coupling rib protruding from a front end thereof, to be inserted in the third coupling opening, wherein the third coupling rib includes: a third protruding portion protruding outward from an end of the second front end portion of the side plate; and a third bending portion (321b bent upward from the third protruding portion, wherein, the side plate being coupled with the inner case, the third protruding portion is inserted in the third coupling opening. a third protruding portion protruding outward from an end of the second front end portion of the side plate; and a third bending portion (321b bent upward from the third protruding portion, wherein, the side plate being coupled with the inner case, the third protruding portion is inserted in the third coupling opening.