This paper describes the attitude control system of the REIMEI satellite: a 70 kg microsatellite for scientific aurora observation. One of the instruments for the observation is an aurora imager, thus three axis attitude control capability of 0.5 deg accuracy was required. To achieve the requirements within limited resources, such as mass, volume, electrical power, cost or human resource, unique approaches were taken for design, test and operation of the attitude control system. Some of these points are introduced in this paper with in-orbit evaluation results.