JT-60 is a large tokamak device now under construction at the Naka site of Japan Atomic Energy Research Institute. Its objective is to investigate plasma confinement and heating in reactor-grade hydrogen plasmas and to conduct an integrated test of associated fusion technologies. It has a long-pulse capability of 5–10 sec in pulse length and features, among others, a magnetic limiter (divertor), various methods of supplementary heating, and radiofrequency current drive. Construction of the JT-60 device, started in April 1978, will be completed in March 1985. Development of heating devices has advanced on schedule, and full installation of the heating devices of 30 MW in absorbed power in plasmas will be made by July 1986. The present paper describes the JT-60 project for its objective, machine features, status of construction and development, and its experimental program.