In order to bring out the maximum advantages of ozone for applications to the advanced industries, we have developed a continuous 100% ozone generator. The generator consists of four liquid ozone vessels and each vessel repeats the cooling down, accumulation of liquid ozone, ozone gas supply, and evacuation of residual ozone modes. By computer-controlling the modes of the vessels so as to keep the generator ready for continuous ozone supply, 100% ozone of maximum flow rate of 60 sccm at maximum pressure of 2,000 Pa can be supplied within ±1.1 % flow stability through at least 1 week without stopping.