Abstract: A fluid is processed between processing surfaces capable of approaching to and separating from each other, at least one of which rotates relative to the other. A first fluid containing a material to be processed is introduced between processing surfaces 1 and 2, by using a micropump effect acting with a depression 13 arranged on the processing surfaces from the center of the rotating processing surfaces. A second fluid containing a material to be processed, independent of this introduced fluid, is introduced from another fluid path d2 that is provided with an opening d20 leading to the processing surfaces, whereby the processing is done by mixing and stirring between the processing members 1 and 2. In a plane along the processing surfaces, directionality accompanies the introducing direction from the opening of the second fluid into the processing surfaces.