To provide a liquid control valve capable of preventing oil and the like from eluting from an annular seal member and the like of a driving part even if diaphragm valve element is broken, and quickly detecting abnormality such as breakage of the diaphragm valve element.

This chemical fluid control valve 21 comprises a body 22 having a valve opening 28 formed in a middle of a liquid passage 27, a diaphragm valve element 24 for opening and closing the valve opening 28, and a pneumatic driving part 23 for actuating the valve element 24 to be opened and closed and provided with O-rings 14a, 14b at required portions. A diaphragm member 25 is installed between the driving part 23 and the diaphragm valve element 24, so as to prevent liquid from entering the pneumatic driving part 23. Even when the chemical liquid enters from a membrane part 24b, the chemical liquid can be exhausted from a groove 45 via a liquid leakage detection port 45a and detected by a liquid detection sensor.