PURPOSE: To uniformly and evenly diffuse hot water in a chamber by providing integrally a thermal responding body which is deformed by detecting a temperature of hot water supplied to the lower face of a diffusing member, and making the diffusion member freely turnable so that positions of a through-hole and the chamber and variable in accordance with a thermal deformation of the thermal responding body.

CONSTITUTION: When hot water starts to be dripped down to a diffusion plate 16 through a hole 9 from a pipe 3, a thermal responding body 20 detects a temperature of hot water at that time and extends gradually in the vertical direction. By an extension of this thermal responding body 20, a moving cylinder 17 descends and both end parts B, B are opened gradually in the Y direction, and on the contrary, both end parts A, A are narrowed in the X direction. That is, as for the diffusion plate 16, by dripping down hot water, both the end parts B, B are opened gradually, and on the contrary, both the end parts A, A approach, and as a result, positions of through-holes 25... and a chamber 6 become variable gradually as hot water is supplied, and hot water dripping down through the through-hole 25 reaches coffee powder G contained in the chamber 6 uniformly and evenly extending over a wide range.