PURPOSE: To enhance detection accuracy and the stop position accuracy of a laterally moving device, by constituting two preparatory detection sensors and the main sensor arranged therebetween as one set and reducing the moving speed of the laterally moving device when a joint is detected by the mains sensor.

CONSTITUTION: When a coating unit 3 moves from a joint (a) to a joint (a), the castors of a laterally moving device 7 are allowed to tumble in a state contacted with an article (b) to be coated. At this time, if the joint (a) is detected by a preparatory detection sensor 5a or 5c, the laterally moving device 7 is reduced in its speed through a control part and moved at an extremely low speed. At a moment when the joint (a) is detected by a main sensor 5b, a pulse stepping motor is stopped to allow the laterally moving device 7 to stop at the position of the joint (a) and, therefore, the position of the nozzle 12 approaching the main sensor 5b is allowed to also coincide with the position of the joint (a) with good accuracy.