In Japan, Next-generation LEO System (NeLS) research center was established with a support of the Ministry of Posts and Telecommunications (MPT) in the end of 1997. This research center focuses on a study for the LEO system called NeLS which would provide global multimedia mobile satellite services. The target services include up to 2 Mbps multimedia data transmission using handheld or portable terminals. The target year for operation is 2010. This paper describes the current status of technical development of the NeLS project, in terms of satellite constellation, optical inter-satellite link (ISL), satellite antenna, user link, and satellite network.