We report a 54-year-old Japanese man, whose ALT level was 1689 IU/L, without increased gamma-globulin level or autoantibodies. He could not be diagnosed as autoimmune hepatitis (AIH) using scoring systems, and his liver function became normalized after steroid treatment. Recently, AIH with acute presentation of disease and acute-onset AIH without bridging fibrosis have been increasingly reported but cases without the character of increasing gamma-globulin level or autoantibodies before immunosuppressive treatment are extremely rare. This is the third such case report in the literature.