Japan Atomic Energy research Institute(JAERI) and the Institute of Physical and Chemical Research (RIKEN) are going to build an 8GeV synchrotron radiation source in Harima Science Garden City of Hyougo Prefecture. The facility consists of a 8 GeV storage ring of 1436 circumference with a natural emiuance of 7. 2 nmrad. an injector linac of 1 GeV and a 8 GeV synchrotron. Construction starts in 1990 and the first stored beam is foreseen in 1998. At the commissioning time 10 beam lines will be available while the remaining 50 beam lines 32 on insertion devices and 18 on bending magnets will be constructed successively. All these beam lines will be used by external groups.