A refrigerator comprising: a body; a storage compartment defined in the body; a door to open or close an open front of the storage compartment; a storage box having an inner space to store food; and a shelf having a support structure to support food thereon, and protrusion-receiving shelf portions respectively extending along edges of both sides of the support structure and protruding from the support structure, wherein the storage box has slide protrusions respectively formed on both outer side-faces of the storage box at a lower portion thereof, and each of the protrusion-receiving shelf portions has a slide groove to receive the corresponding slide protrusion of the storage box, so that the storage box is able to be slidably mounted/dismounted on/from the protrusion-receiving shelf portions of the shelf, and wherein, when the storage box is mounted on the protrusion-receiving shelf portions of the shelf, food can be put in the inner space of the storage box, whereas when the storage box is dismounted from the frames of the shelf, food can be put on the support structure of the shelf, characterized in that each of the slide protrusions of the storage box comprises a first inclined portion to allow the storage box to move downward as the storage box moves toward a retracted position in the storage compartment, a second inclined portion to allow the storage box to move downward as the storage box moves toward an extended position from the storage compartment, and a balance point separating the first inclined portion and the second inclined portion, the balance point being located at a position nearer a front of the storage box than a rear of the storage box, and the first inclined portion inclines downward from a front side of the storage box to a rear side thereof, while the second inclined portion inclines upward from a front side of the storage box to a rear side thereof. a body; a storage compartment defined in the body; a door to open or close an open front of the storage compartment; a storage box having an inner space to store food; and a shelf having a support structure to support food thereon, and protrusion-receiving shelf portions respectively extending along edges of both sides of the support structure and protruding from the support structure, wherein the storage box has slide protrusions respectively formed on both outer side-faces of the storage box at a lower portion thereof, and each of the protrusion-receiving shelf portions has a slide groove to receive the corresponding slide protrusion of the storage box, so that the storage box is able to be slidably mounted/dismounted on/from the protrusion-receiving shelf portions of the shelf, and wherein, when the storage box is mounted on the protrusion-receiving shelf portions of the shelf, food can be put in the inner space of the storage box, whereas when the storage box is dismounted from the frames of the shelf, food can be put on the support structure of the shelf, characterized in that each of the slide protrusions of the storage box comprises a first inclined portion to allow the storage box to move downward as the storage box moves toward a retracted position in the storage compartment, a second inclined portion to allow the storage box to move downward as the storage box moves toward an extended position from the storage compartment, and a balance point separating the first inclined portion and the second inclined portion, the balance point being located at a position nearer a front of the storage box than a rear of the storage box, and the first inclined portion inclines downward from a front side of the storage box to a rear side thereof, while the second inclined portion inclines upward from a front side of the storage box to a rear side thereof.