PURPOSE: To bond a film having a uniform thickness on the entire surface of a work by making it possible to automatically correct the revolving position of a spray pattern corresponding to the moving direction of a painting gun.

CONSTITUTION: A painting gun 16 is controlled on the basis of preliminarily inputted data so as to move along a predetermined operating locus. The spray pattern correcting means 18E of a control apparatus 18 corrects the revolving position of a spray pattern so that the oval spray pattern sprayed from the gun 16 holds a definite direction with respect to the moving direction of the gun 16. As a result, teaching operation is simplified as compared with a conventional apparatus and can be completed within a shorter time. Further, the shift of the revolving position of the spray pattern can be reduced and a film having a uniform thickness can be bonded and formed on the entire surface of a work.