A coating machine enables the inside of a paint chamber to be washed clean with less amount of use of thinner by increasing washing efficiency and is capable of forming a coating with uniform coating thickness by always uniformly jetting a paint over 360° about a rotary atomizing head and the rotary atomizing head of the coating machine. The coating machine includes the rotary atomizing head in which the paint chamber is formed in the clearance between an outer bell fitted to the tip of a tubular rotating shaft and an inner bell fitted to the front side of the outer bell. Fins agitating, in the paint chamber, a washing fluid supplied from a thin tubular nozzle inserted into the tubular rotating shaft are radially formed on the rear surface side of the inner bell. An annular paint groove temporarily accumulating the paint is formed in the inner surface of the rim part of the outer bell on which the paint jetted from the paint jetting holes formed at the peripheral surface part of the paint chamber is extended.