Research project of "Soft fluid actuator" has been promoted in Okayama University. This project is organized by different field researchers; robotics, mechatoronics, health and medical researchers. Soft fluidic actuators are configured with polymer material and driven by fluid (pneumatic and hydraulic) pressure. Therefore they will have many advantages; high compliance, light weight, low cost and non-electrical drive. Namely they are breakthroughs of the realizations of highly safe mechanisms. In the project, not only fundamental researches of new soft fluid actuators but also applying them to medical and welfare mechanical systems have progressed. In this paper, the concept and purpose, the organization, and some researches of the project are introduced.