<p>A chemical supply system in which suction or delivery flow rate of chemical is controlled with high precision while troubles incident to heat generation is removed. In a chemical supply pump (10), a bellows partition member (12) as a variable volume member is housed in a pump housing (11) which is used to section a pump chamber (13) from a pressure action chamber (14). The pressure action chamber (14) is connected with an electro-pneumatic regulator (28). The bellows partition member (12) is coupled with a rod (33) and moving amount of which is detected by a position detector (36). A controller (40) sets a target working amount of the bellows when the chemical is sucked or delivered, and controls the electro-pneumatic regulator (28) based on the difference between the target working amount and an actual working amount determined from detection results by the position detector (36).</p>
