A semiconductor wafer held by a holder within a chamber is irradiated and heated with halogen light emitted from multiple halogen lamps. A cylindrical louver made of opaque quartz and a light-shielding member of a ring shape having a cut-out portion are provided between the halogen lamps and the semiconductor wafer. When the semiconductor wafer is heated with the light emitted from the halogen lamps, a shadow region will appear in the semiconductor wafer as a result of the louver blocking off the emitted light. However, in the presence of the cut-out portion of the light-shielding member, the light emitted from the halogen lamps will reach the shadow region through the cut-out portion. This configuration allows the shadow region to be heated in the same manner as the other regions, and accordingly will help make uniform the in-plane temperature distribution of the semiconductor wafer during light irradiation heating.