To prevent the occurrence of a crystal defect in a semiconductor substrate at the time of executing heat treatment by making the semiconductor that at least at a heat treatment temperature in a state that the semiconductor substrate is loaded.

When a film-like body 8 made of Si is loaded on a boat 2 so that it becomes a projecting form in an upper direction, the warp of the film-like body 8 reduces to 120μm with the self-weight of the film-like body 8. When the Si substrate whose diameter is 300mm and thickness is 725μm is loaded on the film-like body 8, the Si substrate 1 pushes down the film-like body 8 by 120μm by means of the weight of the Si substrate 1. Thus, the warp by means of the weight of the Si substrate 1 and the warp quantity (a) of the film-like body 8 are canceled, and the Si substrate 1 becomes plane. Since large stress is generated in the film-like body 8 in such a state, the semiconductor substrate 1 on the film-like body 8 is held almost horizontally in a state without the warp. Thus, stress hardly occurs in the semiconductor 1. Since the heat treatment of high temperature is executed in such a state, the defects of slip and the like do not occur.