A refrigerator comprising: a main body including an inner case and an outer case; a storage chamber (50, 60) having an opened front portion and provided in the inner case; a sliding door opening and closing the opened front portion of the storage chamber; a support frame movably supporting the sliding door with respect to the main body; and a storage basket being drawn into and out of the storage chamber while being moved together with the sliding door when the sliding door is opened and closed, and supported by the support frame, wherein the storage basket includes sidewalls (250a,b), each of the sidewalls includes a first wall and a second wall formed on an upper portion of the first wall so as to protrude toward the inner case, and the support frame is disposed between the first wall and the inner case, a roller support surface is provided on the second wall, a roller support guide is provided on the roller support surface, a front protrusion is configured to protrude upward from a front portion of the roller support surface; and a rear protrusion is configured to protrude upward from the rear portion of the roller support surface; characterized in that an auxiliary protrusion is configured to protrude upward from the roller support surface; the auxiliary protrusion is configured to protrude upward between the front and rear protrusions of the roller support surface, the auxiliary protrusion is formed so as to be closer to the front protrusion than the rear protrusion between the front protrusion and the rear protrusion, and the second wall has a vertical length greater than a vertical length of the first wall. a main body including an inner case and an outer case; a storage chamber (50, 60) having an opened front portion and provided in the inner case; a sliding door opening and closing the opened front portion of the storage chamber; a support frame movably supporting the sliding door with respect to the main body; and a storage basket being drawn into and out of the storage chamber while being moved together with the sliding door when the sliding door is opened and closed, and supported by the support frame, wherein the storage basket includes sidewalls (250a,b), each of the sidewalls includes a first wall and a second wall formed on an upper portion of the first wall so as to protrude toward the inner case, and the support frame is disposed between the first wall and the inner case, a roller support surface is provided on the second wall, a roller support guide is provided on the roller support surface, a front protrusion is configured to protrude upward from a front portion of the roller support surface; and a rear protrusion is configured to protrude upward from the rear portion of the roller support surface; characterized in that an auxiliary protrusion is configured to protrude upward from the roller support surface; the auxiliary protrusion is configured to protrude upward between the front and rear protrusions of the roller support surface, the auxiliary protrusion is formed so as to be closer to the front protrusion than the rear protrusion between the front protrusion and the rear protrusion, and the second wall has a vertical length greater than a vertical length of the first wall.