PURPOSE: To prevent an uneven processing of a photosensitive material by installing a cover for surrounding a space containing the upper space of a processing tank and installing an exhaust means in this cover so that an air current is generated in the upper part.
CONSTITUTION: In the upper part of a carrying-in port 65 of the upper part of a cover side wall 60, a suction port 10 is formed, and on the upper part of a cover side wall 61, an exhaust port 11 is formed, and in this exhaust port 11, a fan 12 is installed. By operating this fan 12, the open air is led into a first space 6a from the suction port 10, passes through the upper part of a first space 6a, and exhausted from the exhaust port 11. In this case, an air current 15 formed by suction and exhaust air is in the upper part of a first space 6a, therefore, especially, dewing on the inside of the upper face of a cover 6 can be prevented, and also, air being in the vicinity of a liquid level of processing liquids 20, 30 is not disturbed, therefore, evaporation, etc., of the processing liquids 20, 30 can be suppressed. In such a way, an uneven processing of a photosensitive material S can be prevented.