This paper surveys the role of technological developments in Japanese environmental problems. After summarizing the brief history of Japanese pollution problems, we examine effects of regulations and investment for pollution control. In Japanese case, pollution control regulations promoted investment which embodied new pollution control technology. As for exhaust desulfurization technology, Japanese companies improved imported technology and diffused desufurization facilities which contributed to decrease SOx emissions. We also focus on energy saving technology which control CO2 emissions Japanese energy saving technology such as continuous casting process was developed and diffused in the late 1970s and the early 1980s due to the oil shock. However, more energy saving technology is required for fear of stopping the global warming. Several techological developments in supply side in electric utility are in progress.