A fluid mixer for mixing a first fluid and a second fluid includes an introducing component having a bore, a cylindrical component fitted into the bore of the introducing component and a mixing component having a conical recess and on which the introducing component and the cylindrical component are held. A first introducing flow path receives the first fluid and a first distributing flow path distributes the first fluid over the whole circumference of the cylindrical component. A second introducing flow path receives the second fluid. A second distributing flow path distributes the second fluid so that the first fluid and the second fluid are alternately arranged in an circumferential direction. A joining part joins together the first fluid and the second fluid fed with the fluids alternately arranged circumferentially.