Heat shield plate for substrate annealing apparatus

A heat shield plate for a substrate annealing apparatus is provided with a horizontally supported flat-plate-like substrate , a heater positioned above the substrate to heat the upper surface of the substrate with radiation heat, and a heat shield plate horizontally movable between a shielding position where the substrate is shielded from heater and an open position out of the shielding position. The heat shield plate is composed of a structural member made of a low thermal expansion material (carbon composite material) which is hardly deformed due to a temperature difference in the shielding position, and a heat insulating member which covers the upper surface of the structural member and keeps the surface at an allowable temperature or below.