<p>The present invention provides an SN plate capable of being formed in a large size while using a highly corrosion resistant and highly thermally expansible refractory product. In the SN plate of the present invention, a specific refractory member 1a having a thermal expansion rate as measured at 1500°C of 1.15 to 2.50% due to addition of aluminum for improving corrosion resistance is arranged as a part of the SN plate to cover at least a practically critical region of the SN plate. A thickness of the specific refractory member is set in a range of 15 to 25 mm. A portion of the SN plate other than the specific refractory member is made up of an unburned or burned refractory product consisting primarily of an alumina-carbon composite.</p>