The International Thermonuclear Experimental Reactor (ITER) is an experimental thermonuclear tokamak reactor that will test some new technologies of physics. The conceptual design activity of ITER required the joint work at a technical site at the Max Plank Institute for Plasma Physics in the Garching Germany from 1988 to 1990. The proposals from Japan are summarized by the Fusion Experimental Reactor (FER) Team and the Superconducting Magnet Laboratory of the Japan Atomic Energy Research Institute (JAERI). This paper describes the Japanese contributions to the utility (power supply and cryogenic system) for the magnet system of ITER. The concepts of a magnet utility design were based on the construction experiences of the domestic test facilities of the Large Coil Task and of the JAERI`s Demo Poloidal Coil program. During the conceptual design phase, it is important to know what parts are critical for construction and what subjects need development. In the power supply system, the DC beakers shall be modified to compact size. Several cryogenic components also require scale-up development during the engineering design phase. (author).