To establish a product passage when a valve stem is sufficiently depressed and supply a product only from a quantity adjustment chamber.

A valve housing 22 holds in it an annular flange 66 and a compression spring 28 together with a valve gasket 30 which closes an internal cavity 24. The valve housing 22 is attached to a ferrule 8 such that the stem 34 of the valve system 26 projects through holes defined in the valve gasket 30 and ferrule 8. The stem 34 includes a discharging passage which is normally closed by the valve gasket 30. One of the underneath of the annular flange 66 and the contact face of the valve housing 22 has a compressive sealing member 68, and the other has an annular edge 70.