A refrigerator comprising: a cabinet suitable for being installed to pass through or inserted into a door or a wall and having walls forming a storage compartment for storing goods; a housing coupled to or formed integrally with a part of the cabinet; an outdoor side door configured to open or close a front side of the storage compartment and exposed to an outside of a space, the door or the wall being a boundary of the space; an indoor side door configured to open or close a rear side of the storage compartment and exposed to an inside of the space; a cold air supply device, at least a part of which is disposed in the housing, configured to make air in the storage compartment cold; and an inner gasket surrounding an edge of the indoor side door, characterized in that the refrigerator further comprises a guide rib extending along at least a portion of an edge of a rear surface of the cabinet; and a rear discharge port formed at a rear surface of the housing and allowing air in the housing to be discharged therethrough, wherein the guide rib protrudes a predetermined distance from the rear surface of the cabinet and extends along an edge of the cabinet, wherein, when the indoor side door is closed, the guide rib is configured to substantially come into contact with a rear surface of the indoor side door, and an air pocket is formed by the rear surface of the cabinet, the guide rib, the inner gasket, and the inside surface of the indoor side door, and wherein both ends of the guide rib are positioned near a left side and a right side of the rear discharge port, such that the guide rib is configured to guide the air discharged through the rear discharge port to rise and flow into the air pocket to evaporate condensation formed around the inner gasket. a cabinet suitable for being installed to pass through or inserted into a door or a wall and having walls forming a storage compartment for storing goods; a housing coupled to or formed integrally with a part of the cabinet; an outdoor side door configured to open or close a front side of the storage compartment and exposed to an outside of a space, the door or the wall being a boundary of the space; an indoor side door configured to open or close a rear side of the storage compartment and exposed to an inside of the space; a cold air supply device, at least a part of which is disposed in the housing, configured to make air in the storage compartment cold; and an inner gasket surrounding an edge of the indoor side door, characterized in that the refrigerator further comprises a guide rib extending along at least a portion of an edge of a rear surface of the cabinet; and a rear discharge port formed at a rear surface of the housing and allowing air in the housing to be discharged therethrough, wherein the guide rib protrudes a predetermined distance from the rear surface of the cabinet and extends along an edge of the cabinet, wherein, when the indoor side door is closed, the guide rib is configured to substantially come into contact with a rear surface of the indoor side door, and an air pocket is formed by the rear surface of the cabinet, the guide rib, the inner gasket, and the inside surface of the indoor side door, and wherein both ends of the guide rib are positioned near a left side and a right side of the rear discharge port, such that the guide rib is configured to guide the air discharged through the rear discharge port to rise and flow into the air pocket to evaporate condensation formed around the inner gasket.