High Pressure Institute of Japan, HPI, was established in 1963 and one year later, I joined with the Japan Steel Works. Since that time I have been continuing to participate in pressure vessel technology. So, my technical activities in HPI were almost all of my background. On the occasion of honorable lecture for HPI 50 years anniversary, I would like to look back to improvement of pressure vessel technology in recent half century as much as my related activities and also try to foresee future advancement.