Abstract: A fluid processing device purifies water, oil, or gas, and also mixes water and petroleum oils to form an emulsion. The device has a spiral tube having a central through-hole bored and a spiral communication fluid path surrounding the through-hole. A continuous porous filter is enclosed in the through hole. Fluid can pass not only within the filter but also along the spiral tube surrounding the filter. Even if clogging is produced at the flowing-in side of the filter, fluid still passes through the spiral path and is sent to the inside. The spiral communication hole path becomes a bypass and fluid enters the filter from multiple directions, whereby the contact area is enlarged.