To prevent a solution from making cavitation in a conduit run to a delivery from a tank and to prevent the occurrence of dispersion of film thickness even when it is applied for coating, etc.

A chemical tank communicates with a deliverer 30 by a piping 12 in which a pressure sensor 40 and an air operated valve 50 are serially interposed, and relation of pressure in the piping 12 and delivery quantity of the deliverer 30 is previously measured and memorized in a memory device as a data table. Thereafter, at the time of delivery a chemical solution, target pressure Pt is retrieved from the data table in accordance with delivery quantity Qt to be provided, when this target pressure Pt is within a specified range against pressure Pa in the piping 12 detected by the pressure sensor 40, opening valve control of the air operated valve 50 is carried out, and when the target pressure Pt is out of the range against the pressure Pa, delivery is not carried out but pressure in a tank 10 is controlled.