Recently, Demands of automatic X-ray film processors are increasing more and more at general hospitals and private clinics, but various troubles because of incorrect control were found out. Authors have researched to find out the function and activity of automatic X-ray film processor for 70 days with Kodak X-OMAT processor, and results obtained were as follows; 1. Automatic X-ray film processor have an advantage to conduct the rapid treatment of X-ray film processing, but incorrect handling of developing and fixing agents were brought about a great change in contrast and optical density of X-ray film pictures. 2. About 10,000 X-ray films could be finished by same developing and fixing solution without exchanging any other solutions in automatic X-ray film processor.