Provided is an automatic spray gun which has a reduced number of components to be washed. This automatic spray gun (1) is provided with: a spray gun main body (11) formed from a front end unit (2), a middle unit (3), and a back end unit (4); a gas cap (5) attached to the front end unit (2); a liquid nozzle (6) attached to the middle unit (3); and a needle (8 for opening and closing the liquid nozzle (6). A through hole (20) is formed in the front end unit (2) going toward the middle unit (3) from the front side where the gas cap (5) is provided. The middle unit (3) is provided with: a protrusion (30) which is inserted into the through hole (20) of the front unit (2); and a through hole (34) that is linked to a liquid supply opening (31) provided in the middle unit (3) and passes through the protrusion (30), which is formed toward the back end unit (4) side from the front end unit (2) side. The liquid nozzle (6) is attached to the through hole (34) of the protrusion (30). The needle (8) passes through the through hole (34) of the middle unit (3) from the back end unit (4 side, and the tip of the needle (8) which can be inserted into and removed from a tip opening of the liquid nozzle is inserted therein.