To control the occurrence of light-amount unevenness even in case an environmental change occurs.

LPH 14 is equipped with a printed circuit board 52 which mounts LED array composed by putting in order 60 pieces of LED chips in which 128 pieces of LED are installed and a rod lens array 54 composed by aligning two or more rod lens in two trains. The luminescence light-amount of each LED is corrected using LED correction data which are established from individual light amount unevenness of LED and the pitch unevenness of rod lens. Considering the positional gap which is generated by the expanding and contracting of the printed circuit board 52 and rod lens array 54 due to a temperature changing, the lens correction data are changed according to the temperature. Concretely, the culling or adding data from or to lens correction standard data are performed according to the temperature, and then the lens correction data are made out.