To securely and accurately perform the intermittent supply work of liquid by a simple mechanism by supplying liquid by a fixed amount intermittently due to the rotation of a four-way valve.

When insecticidal liquid stored in a tank 2 is applied to an insect pest exterminating device supplying it to a transpiration plate 18 intermittently, the transpiration plate 18 is first heated, and a rotator of a four-way valve 6 is rotated by a drive mechanism 13 when the plate 18 reaches a predetermined temperature. When a position detection sensor detects that the rotator of the four-way valve 6 reaches a detection position, the rotator is stopped, and a flow hole of the rotator is stopped at a position where it is connected with holes 7, 9. Consequently, a passage in which insecticidal liquid in the tank 2 is refluxed into the tank 2 through hoses 14, 15 is formed. After a predetermined period of time elapses, the rotator 11 is rotated by 90° to communicate holes 8, 10, and the insecticidal liquid in the flow hole of the rotator is supplied to the transpiration plate 18 by placing it on the air from a blower 20.