To use a reflecting plate of a simple shape for a heating device with the excellent heating efficiency and excellent temperature uniformity of a molding mold.

Infrared lamp heaters 1 irradiate infrared rays. Each fixing jig 2 holds the infrared lamp heater 1 individually. Gold plating 7 is applied to side faces of a transparent quartz tube 3 with its inside face in a smooth cylindrical shape, and the infrared rays irradiated from a plurality of the infrared lamp heaters 1 arranged inside the cylindrical shape are reflected toward the direction of a center axis of the cylindrical shape. The molding molds are arranged at positions on the center axis in the transparent quartz tube 3. The fixing jigs 2 of the same shape are overlapped on one another, so that the infrared lamp heaters are arranged at the same intervals in a direction parallel with the center axis in the quartz tube 3.