Abstract: The present invention relates to a reaction apparatus for receiving a reaction gas and for heating a substrate so as to form a film such as an insulating film on the substrate or for etching, with reduced power consumption for heating the substrate. The apparatus can change a substrate temperature within a short period of time, and maintains throughput while reducing labor and cost for maintenance. The apparatus includes a substrate holder (12) with a base of an insulating material in which an electrode (22) and a heater (23) for heating the held substrate (20) are contained. The apparatus also includes a processing chamber (7) enclosed by a chamber wall (7a).