PURPOSE: To perform spraying without waste, by registering a spray pattern corresponding to the kind of a truck and discriminating the kind of the truck immediately before the truck passes a fixed gun while performing the ON/OFF control of the fixed gun corresponding to the spray pattern.

CONSTITUTION: When a reading signal is supplied to CPU22 from a truck discrimination apparatus 17, the discrimination processing of the truck is performed and the discriminated result is successively stored in memory 23. CPU22 detects the movement of the truck on the basis of the conveyer pulse outputted from a conveyer synchronizing apparatus 18 and reads the truck number from the memory when the truck reaches a position immediately before a fixed gun 14 to search for the spray pattern of the corresponding fixed gun. A robot 12 is regenerated by turning a start switch 13 ON when the truck reached a predetermined position and the spraying of a release agent by the predetermined spray pattern is performed from the fixed gun 14 by turning a start switch 15 ON.