In the most field of today's technology we can recognize that they are being developed faster than any other era. The common phenomena of the current technology are; large in scale, complicate in process, exposed to large number of people. Although it certainly has contributed to the welfare of humankind, we could realize that the technology has adverse effect to us. Actually we had to experienced numbers of disastrous accidents from many fields modern technologies are being adopted. Hundreds of people, sometimes thousands of people had to die without being noticed why and when. It is clear that we have to manage the risk existing in modern technology. In this paper I wanted to direct they way to adjust the public concerning to the public safety by introducing the method of risk assessment, acceptable risk criteria, and risk management model.