PURPOSE: To prevent a measuring error due to expansion or the like of a tube, and achieve a high precision measurement and discharge by providing a discharge port disposed at a position covered with a cylinder forward end aperture in the inner surface of the bottom part of a container and connected to the outside.

CONSTITUTION: A cylinder 50 and a plunger 60 are retracted to put them apart from the bottom surface where a discharge port 30 is disposed, so fluid 3 is led into a space formed between the respective forward end and the discharge port 30. The cylinder 50 only is then moved forward to get its forward end in contact with the bottom surface and close the space, so a constant quantity is separated for the fluid 3 previously put in the space to be enclosed in the cylinder 50. By then moving the plunger 60 forward, the fluid in the cylinder 50 is pressurized and discharged from the discharge port 30 in order. Fluid discharged from the discharge port 30 is kept in a constant quantity correctly corresponding to the stroke of the plunger 60 and the inner diameter of the cylinder 50.