To apply coating material sufficiently to the entire surface of an article to be coated having depth and unevenness.

A box body 1 to be coated is transported in a main body box 11 by a conveyer 13. Guns G1-G4 are held on the circumference of a rotor 31 slantingly to the radial direction. Coating material is sprayed from each gun G1-G4 to the box body 1 which is transported by the conveyer 13 while the rotor 31 is being rotated normally/reversely in the vertical direction around a rotary shaft 32 by driving a motor 33. By rotating the rotor 31 normally/ reversely, each gun G1-G4 can take positions of four directions of an upper side position, a left side position, a lower side position, and a right side position to the box body 1, and accordingly each gun G1-G4 sprays coating material to each surface of the box body 1 from four directions so that uniform coating can be done.