PURPOSE: To protect the outer peripheral surface of the barrel of a spray gun for electrostatic coating against contamination with the coating material sprayed thereby into the air by providing the barrel of the spray gun near its rear end with an air outlet opening through which a stream of air is delivered toward the front end of the barrel around the outer periphery thereof.

CONSTITUTION: The barrel 2 of an electrostatic coating spray gun 1 is provided near its rear end with an air outlet opening 22, through which a stream of air is delivered toward the front end of the barrel 2 around the outer periphery thereof so as to form an air curtain throughout its length in such manner as to enclose its outer periphery, thereby protecting the outer peripheral surface of the barrel from contamination with the coating material sprayed into the air from a nozzle 3. As a result, there is no need for cleaning the barrel 2 frequently or laying a cover thereon to permit continuous coating operation with improved operational efficiency.