To adjust the amount of liquid to be supplied and to avoid the complexity of the composition of an apparatus for supplying liquid quantitatively when liquid stored in a storage tank is supplied quantitatively to the outside of the tank, and to facilitate operation for the adjustment.

In an apparatus, a float 33 which can move vertically with the variation of the level 32 of liquid 16 stored in a storage tank 21 is provided. A flexible discharge pipe 39 in which one end part is made a liquid introduction part 37, fitted to the float 33, and opened in liquid 16 near a liquid surface 32, the other end part side is extended downward from the liquid introduction 37 side, the other end part is made a liquid discharge part 38 and opened to the outside of the tank 21, and its inside apace is made a discharge passage is installed. A flow rate adjusting means 55 which makes the opening of the opening 37a of the liquid introduction part 37 variable.