PURPOSE: To provide a valve excellent in the easiness in the maintenance works, quantitative determination, etc., by furnishing a plurality of liquid distribution passages adjacent to a straight passage furnished inside a passage block, installing diaphragm in such an arrangement as enclosing individually a plurality of coupling parts which couple the straight passage with the liquid distribution passages, and controlling the pressure contacting of diaphragm.

CONSTITUTION: A straight passage 2 is provided as stretching in the longitudinal direction of a passage block 1 by a boring process, and a tube etc., for a reagent vessel etc., is connected with this straight passage 2. A plurality of recesses having a circular section are formed along the straight passage 2 in the block 1, and liquid distribution passages are provided at the bottom surfaces of the recesses in such a way as penetrating. The end openings 3'-1 thru 3'-5 of the liquid distribution passages and the spaces A-E adjacent to the straight passage 2 are used as coupling parts (valve part), and these coupling parts A-E are enclosed with diaphragm 5. When a positive pressure is applied to the diaphragm 5, the end openings 3'-1 thru 3'-5 are blocked-when a negative pressure is applied, the end openings are left open.