To provide a fluid processing apparatus and method which enable a production of a mixture of fluids with particles of controlled or fine particle diameter dispersed.

The fluid processing apparatus is provided with first and second passages 20a, 20b adjacent through a porous body 22, and fluid transportation means 18a, 18b transporting continuously or intermittently each of first and second fluids 14a, 14b to these passages, wherein the first fluid 14a is flowed out through the porous body from the first passage to the second passage to turn into particles 30 and is flowed together with the second fluid 14b. The apparatus has a departure promoting means to allow the fluid particles leaked from the surface of the porous body to depart from the porous body early.