Heat reflecting plate

The purpose of the present invention is to provide a heat reflecting plate which has low heat capacity, can be made energy-saving, has high reflectance, suppresses contamination to the inside of a furnace, and has excellent thermal responsiveness. This heat reflecting plate (100) is provided with: a plate-shaped exterior (1); and a reflector (5) which is disposed inside the plate-shaped exterior (1), the outer periphery of which is completely covered by the plate-shaped exterior (1), and which reflects infrared rays incident on one surface of the plate-shaped exterior (1). The reflector (5) is a film, plate, or foil, and the total heat capacity in the thickness direction of the plate-shaped exterior and the reflector in 1 mm2 of the heat reflecting plate (100) is 0.0004-0.0080 J/K. 本发明的目的在于提供一种热反射板，其热容较小，可节能化，具有高反射率，抑制对炉内的污染，且热响应性佳。本发明的热反射板是热反射板100，其具有：板状外装1；及反射体5，其配置在板状外装1的内部，外周围完全被板状外装1覆盖，且对入射至板状外装1的一表面的红外线进行反射；且反射体5是薄膜、板或箔，热反射板100的1mm2中的板状外装及反射体的厚度方向的合计热容为0.0004～0.0080(J/K)。