PURPOSE: To easily clean the surface of a heat treatment plate by a method wherein a substrate support pin and a shutter work in conjunction with each by a single driving means and the substrate support pin and the shutter are moved up and down in a nearly opposite phase.

CONSTITUTION: A support member 15 situated at the lower part of a heat treatment plate 1 is driven upward by a driving means. Then, a substrate support pin 14 supported by the support member 15 is raised; its tip part protrudes on the surface of the heat treatment plate 1; the carrying-in and carrying-out waiting state of a substrate W is set. When the support member 15 is raised and driven, one end of an inclination movement member 28 coupled to it is raised and the other end is lowered. As a result, a shutter 24 coupled to the other end of the inclination movement member 28 is lowered, and a substrate feed and discharge port 8 installed at a cover 6 is opened. That is to say, the shutter 24 is raised and lowered, via the inclination movement member 28, in a state that it is nearly in an opposite phase to the substrate support pin 14. Thereby, the surface of the heat treatment plate 1 can be cleaned easily.