A gyrating nozzle head spray gun includes grip including air inlet, valve seat, gas-delivery tube connected to valve seat and terminating in mating connection screw rod and trigger operable for letting external compressed air go into air inlet and gas-delivery tube, attachment tube connected to mating connection screw rod of the gas-delivery tube, gyrating nozzle head assembly including gas-supply tube connected to mating connection screw rod and suspended in attachment tube, bearing, cap, linking module and gyrating nozzle head mounted on one end of the gas-supply tube, and water-delivery tube having one end extended bottom of coupling hole of gas-delivery tube and connected to water tank for sucking in water and opposite end thereof inserted through gyrating nozzle head for ejecting fluid for creating mist of fine droplets upon ejection of compressed air through the gas-supply tube and oblique jet hole and central axle hole of the gyrating nozzle head.