The Laboratory for Space Systems (LSS) in Tokyo Institute of Technology has developed a small satellite named "TSUBAME", which has two main missions: polarized gamma-ray observation by high speed maneuver, and earth observation with a small optical camera. In addition, the Micro-CMG, which has been jointly-developed by LSS and TAMAGAWA SEIKI Co., Ltd., is one of the most important devices to achieve the high speed maneuver and high accuracy control. The object of this paper is to introduce the system and Engineering Model development of TSUBAME.