PURPOSE: To obtain an image with constant color balance by making the temperature and humidity of the exposure part of a printer constant when a silver halide color photosensitive material is exposed by a printer.

CONSTITUTION: An air supplying part 50 for holding the exposure part 31 at constant temperature and constant humidity is installed in the exposure part 31. An air discharging fan 53 which discharges the air in the exposure part 31 to the outside is installed in the air supplying part 53 and distributors 54 and 56 for distributing the discharged air at a specific ratio are installed. The distributor 54 is driven by a motor 58, which is connected to a control means 61. When the silver halide color photosensitive material is exposed by the printer, the temperature and humidity of the exposure part of the printer are held constant to make color balance constant. Consequently, the problem of, specially, reciprocity law failure due to humidity is eliminated and the image with the constant color balance is obtained.