Since 1984,the National Institute of Polar Research and the Institute of Space and Astronautical Science have studied the feasibility of a long duration circumpolar balloon experiment, called Polar Patrol Balloon (PPB) project. This project aims at establishing a PPB system to bring scientific playloads in the stratosphere over the Antarctic region by large zero-pressure balloons. Three test balloon flights in 1987 and 1989 at Syowa Station have shown that the PPB would have a good condition of coming back to the Iaunching site during the summer season in Antarctica. The PPB experiments for scientific observation were consequently carried out since 1991. It would be necessary to continue, because we have a lot of interesting research subjects in many scientific fields in the Antarctic region. This paper will describe the summary of the balloon launching system and the scientific ballooning technology of the PPB project.