The single substrate thermal processing apparatus (2) includes a process chamber (5) arranged to accommodate a target substrate (W) and provided with a showerhead (10) disposed on its ceiling. A support member (28) is disposed to support the target substrate (W) so as for it to face the showerhead (10), when the target substrate (W) is subjected to a semiconductor process. A heating lamp (30) is disposed below the support member (28), for radiating light to heat the target substrate (W). The support member (28) and heating lamp (30) are moved up and down together relative to the showerhead (10) by an elevator mechanism (20). The elevator mechanism (20) sets different distances between the showerhead (30) and heating lamp (10), in accordance with the different process temperatures, thereby causing temperature change of the bottom surface of the showerhead (10) to fall in a predetermined range.