PURPOSE: To enhance the contact efficiency of gas-liquid-solid, by covering the under surface of the outer edge of the downward dish shaped cap fixed to the upper end of a dispersing cylinder with the thin disc shaped plate having elasticity engaged with and fixed to the dispersing cylinder at a position lower than the outflow port of said cylinder.

CONSTITUTION: The gas-liquid mixed phase fluid flowed in a dispersing cap 9 pushes down a plate 8 as shown by a dotted line by the pressure of said fluid to be injected from the gap between the dispersing cap 9 and the plate 8. This gap is forcibly widened on the basis of an angle θ and becomes large toward the outside and enhances the dispersing effect when the fluid is injected. Because the plate 8 has elasticity, said plate 8 vibrates when the gas-liquid mixed phase fluid is injected to be finely divided and gas is formed into fine bubbles. When no fluid is injected, the plate 8 is contacted with the cap 9 and, therefore, a solid particle such as a catalyst is prevented from penetrating in a mixed bed 5 from a dispersing cylinder 4.