PURPOSE: To measure a micro delivery quantity of liquid with high accuracy by sucking/delivering the liquid through elastomer which is interlocked with the motion of a valve to expand and shrink.

CONSTITUTION: A precise measuring delivery device 1 comprises an electromagnet 2 and a measuring delivery section 3. A valve member 13 comprises a diaphragm 13c having waved cross-section and a valve body 13d for opening/closing a suction port 14a and integrally made from tetra ethylene fluoride resin. When a rectangular wave is applied to a coil 6, a plunger 7 moves up and down in response to the rectangular wave and the valve body 13d opens/closes the suction port 14a. Here, the valve body 13d moves up and down corresponding to the motion of the plunger 7, but the diaphragm 13c follows with a slight delay because of its resiliency. Since the liquid is sucked gradually and naturally, micro quantity of liquid can be sucked corresponding to the difference of the resistance of the liquid without producing bubbles.