A process fluid circulation type processing system has a processing apparatus that supplies a process fluid to a workpiece held on a chuck table. A process fluid supplying apparatus adds a surface active agent to pure water to produce the process fluid at a predetermined concentration and then supplies the process fluid to the processing apparatus. A pure water generating apparatus removes processing dust and impurities including the surface active agent from waste fluid discharged from the processing apparatus to thereby generate the pure water and then supplies the pure water to the process fluid supplying apparatus. The process fluid supplying apparatus includes a pure water passage, a pure water flow meter for measuring the flow rate of the pure water, and a surface active agent supplying unit for supplying the surface active agent to the pure water downstream of the pure water flow meter.