A refrigerator comprising: a heat-insulating main body having an inner casing, an outer casing, and a heat-insulating material filled between the inner casing and the outer casing; a storage compartment formed inside of the heat-insulating main body and having an opening in a front face; a pull-out door which opens and closes the opening on the front face of the storage compartment and which includes a supporting unit (301, 303) provided on an inner board of the pull-out door and configured to support a container provided inside of the storage compartment; a rail device which makes the container movable forward and backward as the pull-out door opens and closes; and a door frame which is fixed to the pull-out door, joined to the rail device, and holds the container, wherein the rail device includes: a fixed rail fixed with respect to the storage compartment; and a movable rail (222, 223) connected to the pull-out door, movable forward and backward along the fixed rail, provided below a center of the pull-out door (201, 530) in a vertical direction, and which supports the container, and wherein the container includes on a front face, a flange portion that is detachably inserted in the supporting unit (301, 303) such that the container is fitted in and supported by the pull-out door so as to be vertically attachable to and detachable from the pull-out door, characterized in that the container further includes, on a front side and on a back side, a respective projection (206b, 206c) that, while the container is placed on the door frame, is inserted into a respective hole (205a, 205b) in the door frame. a heat-insulating main body having an inner casing, an outer casing, and a heat-insulating material filled between the inner casing and the outer casing; a storage compartment formed inside of the heat-insulating main body and having an opening in a front face; a pull-out door which opens and closes the opening on the front face of the storage compartment and which includes a supporting unit (301, 303) provided on an inner board of the pull-out door and configured to support a container provided inside of the storage compartment; a rail device which makes the container movable forward and backward as the pull-out door opens and closes; and a door frame which is fixed to the pull-out door, joined to the rail device, and holds the container, wherein the rail device includes: a fixed rail fixed with respect to the storage compartment; and a movable rail (222, 223) connected to the pull-out door, movable forward and backward along the fixed rail, provided below a center of the pull-out door (201, 530) in a vertical direction, and which supports the container, and wherein the container includes on a front face, a flange portion that is detachably inserted in the supporting unit (301, 303) such that the container is fitted in and supported by the pull-out door so as to be vertically attachable to and detachable from the pull-out door, characterized in that the container further includes, on a front side and on a back side, a respective projection (206b, 206c) that, while the container is placed on the door frame, is inserted into a respective hole (205a, 205b) in the door frame. a fixed rail fixed with respect to the storage compartment; and a movable rail (222, 223) connected to the pull-out door, movable forward and backward along the fixed rail, provided below a center of the pull-out door (201, 530) in a vertical direction, and which supports the container, and wherein the container includes on a front face, a flange portion that is detachably inserted in the supporting unit (301, 303) such that the container is fitted in and supported by the pull-out door so as to be vertically attachable to and detachable from the pull-out door, characterized in that the container further includes, on a front side and on a back side, a respective projection (206b, 206c) that, while the container is placed on the door frame, is inserted into a respective hole (205a, 205b) in the door frame.