PURPOSE: To prevent the generation of the spit of a catalyst or paint and to lighten a spray gun by completing the supply of liquid matter to a nozzle by a closing signal and completing the supply of compressed air to the nozzle after the elapse of a predetermined delay time.

CONSTITUTION: When an operation valve 18 is transferred to a closed state by a closing signal and the compressed air in a volume tank 24 is gradually discharged to the outside through a speed controller 26 and an operation valve 18, the pressure in the volume tank 24 lowers to a predetermined value and a delay valve 30 is transferred to a closed state. A delay time, that is, the time before the delay valve 30 becomes a closed state by closing an opening and closing valve after a trigger is returned can be set to a desired value on the basis of the volume of the volume tank 24 and the resistance value against passed compressed air of a speed controller 26. When the delay valve 30 is transferred to a closed state, the supply of compressed air to the air emitting orifice of a spray gun 22 from a third compressed air source AS3 is stopped.