We report a case demonstrating the progressive narrowing of the pancreatic duct, which is presumed to be characteristic of autoimmune pancreatitis, and we review the 37 cases of chronic pancreatitis in which autoimmunity was suggested as an etiological factor in the Japanese literature. A 55-year-old man presented with abdominal discomfort, jaundice, and diffuse swelling of the pancreas on ultrasonography. Serial endoscopic retrograde pancreatography demonstrated the progression of an irregular narrowing of the main pancreatic duct forming diffusely over the course of 2 months. Because the patient had hyperglobulinemia and tested positive for autoantibodies, he was diagnosed as a case of autoimmune chronic pancreatitis. Steroid therapy was carried out with excellent success.