PURPOSE: To prevent liquid from leaking out and scattering by constituting a device such that residual fluid in a fluid circulating pipe can be extruded to a tank side by blowing compressed air after closing an opening/closing valve in each fluid circulating pipe when detached a connector provided in each connecting end of the paired fluid circulating pipes.

CONSTITUTION: In the case of applying to a device for performing delivery of cooling water, when separated a supply side unit P of cooling water from a receiving side unit Q of cooling water, first solenoid valves 5, 6, 12, 13 are closed, to stop circulating the cooling water. Next, solenoid valves 25, 26 of cooling water residual discharge pipes 23, 24 are opened, and also opening a solenoid valve 22 of a compressed air blow pipe 19. In this way, compressed air from a compressed air source 20 is blown into a water supply pipe 8 and a drain pipe 9, left with liquid, through connectors 21, 18 and check valves 16, 17, and the residual liquid is extruded toward the supply side P to flow out into a tank 27 via the residual liquid discharge pipes 23, 24. And then, the solenoid valves 22, 25, 26 are closed to respectively separate connectors 3, 10; 4, 11; 21, 18.