PURPOSE: To shorten a loss time by providing a first process feeding a work in a painting process by a feed truck, a second process detecting the shifts of six degrees of freedom from reference coordinates and a third process synthesizing the respective measured shifts to convert the same to coordinates and feeding back the coordinates to respective painting robots.

CONSTITUTION: A feed rail 2 is connected to a painting station 1 and a plurality of positioning jigs 4... are provided to the dolly truck 3 running on the feed rail 2 to positionally support a car body W. A stopper device 5 is provided under the feed rail 3 to be made engageable with the engaging jig 6 of the dolly truck 3. A plurality of painting robots 7 are provided on both sides of this stop place and a plurality of detectors 8a-8g are provided so as to surround the car body W and six degrees of freedom of the car body W are measured by seven detectors 8a-8g. By this method, the number of painting robots can be reduced.