To suppress or prevent the deposition of a powder paint on the wall of a coating booth at the time of powder-coating an automobile body and further to facilitate such operation as the cleaning in the booth.

In the coating booth 1 for an automobile, the walls 6 and 7 on both sides of the coating chamber 10 for electrostatically power-coating an article 22 and the wall 26 of the collecting chamber for collecting the excess powder paint are formed with PVC. Consequently, the walls 6 and 7 and 26 are prevented from being electrically charged, and the deposition of the fine particles on the wall 6 and 7 and 26 due to the electrostatic attraction is obviated. Further, a self-traveling truck is provided in the booth, and the operation such as the cleaning in the booth is easily performed by an operator.