The present invention discloses a cold gas spraying gun with a powder injector for injecting a gas/powder mixture into a mixing chamber through which a process gas flows. One powder injector pipe of the powder injector is closed at one face end. A delivery opening for delivering the gas/powder mixture from the powder injector is designed as an opening in a side wall of the powder injector pipe. The delivery opening opens into the hollow chamber in the powder injector pipe at an axial distance from the closed face end of the powder injector pipe, and therefore a backed-up volume is located between the delivery opening and the closed end face of the powder injector pipe.