To make exposure constant in a desired range by providing a guide which keeps the distance constant between a surrounding part to shut irradiation of light in directions except a specified direction.

This auxiliary fitting 4 is produced by joining four plates one by one with clasps as to form a square pillar-like surrounding part 1 and installing four pole-like guides 2 in four corners of the surrounding part 1 toward outside of the surrounding part. The tip parts of the guides 2 are covered with protective covers 3. This light irradiation apparatus comprises an irradiation apparatus main body 5 and the auxiliary fitting 4 installed in the light irradiation side. Of the apparatus, the main body 5 is provided with a prescribed number of irradiating apparatuses 9 respectively comprises a light source, a reflecting plate, and a lens and are installed in a supporting pole 10 and made movable up and down and moreover the main body 5 is so connected as to rotate up and down on the joining parts 11 of the main body 5 and the supporting pole 10. Further, a timer 12 is installed in the main body 5 to select the irradiation time.