The utility model discloses a spray gun for little component spraying fireproof paint, including the overcoat handle, big shower nozzle is installed to overcoat handle front end screw thread, the inner bag is installed to overcoat handle inboard, outside and the big shower nozzle outside in inner bag front side is hugged closely, inner bag middle part axial is provided with logical groove, the inner bag is provided with a plurality of runners in leading to the groove periphery, it is provided with the spring mounting section to lead to the groove middle part, it is provided with little spray tube to lead to inslot portion, the activity of little spray tube axial runs through the overcoat handle, little spray tube front end is provided with little shower nozzle, little spray tube periphery is installed in spring mounting section department and is played spring piece. The utility model discloses a spray gun for little component spraying fireproof paint can accomplish the joint spraying of the little spray tube of runner, improves spraying efficiency, can enough guarantee the spraying accuracy of details department through the independent spraying of little spray tube simultaneously, can improve spraying efficiency simultaneously.