PURPOSE: To uniformly and efficiently mix a plurality of kinds of liquid in such case that the viscosity of liquid (liquid A) having a high mixing ratio is large with a plurality of kind of liquid largely different in the mixing ratio at a large amount in a compact device.

CONSTITUTION: Many flow holes 511 are pierced in a metallic sintered compact or a seramics sintered compact having continuous voids. A platelike body made of the metallic or seramics sintered compact is provided in a flow path. While allowing liquid (liquid A) having a high mixing ratio to flow through the flow holes 511, liquid (liquid B) low in a mixing ratio is allowed to permeate through the continuous voids and leached into liquid A from the inner wall surface and the end faces of the flow holes 511 of the mixed platelike body 51. Thereby both liquids are mixed. A mixing device 5 is provided with an introduction hole 522 reaching the vicinities of the flow holes 511 from an injection port, radial distribution grooves 523 and annular distribution paths 524.