Intelligent Space Systems Laboratory, The University of Tokyo (ISSL) and National Astronomical Observatory of Japan (NAOJ) have been developing a small infrared astrometry satellite named "Nano-JASMINE". This is about 50cm cubic and 20kg size and a precedent technical demonstration satellite of JASMINE Project which is programmed by NAOJ and JAXA. Since there has been only one astrometry satellite HIPPARCOS by ESA in the past, Nano-JASMINE is also expected to achieve certain scientific results. In this project, ISSL aims to develop new advanced small satellite bus system which is comparable to large satellite. The performance is from 1 arcsecond attitude control accuracy to 1 mK thermal control. This paper describes about this satellite bus system and current development status.