In recent years, it has been reported a number of application of fluidics to industry. But there is few application to process control. This report deals with an on-off control of pressure in air tank by means of fluidics. The control system is constructed with an air tank, an on-off operation valve, needle valves, an orifice and one fluidic bistable element etc.. The characteristics of elements are examined, and the results is presented. As one of result, it was recognized that the plant consisting of capacitance and restsiction is not the first order element, and about this point a theoretical explanation is offered. This control system is very simple but sufficient results were obtained in respect to the response of system. But in this system, abjustment of supply pressure to a fluidic element is unavoidable in order to get good responses of system. This problem is the subject for a future study
