A premixing chamber of a nebulizing device for an exhaust gas purification system serves to mix a compressed gas such as compressed air, for example, with a reducing agent such as urea solution, for example. The premixing chamber is set up on the carburetor principle and includes a compressed gas feed having a taper and a reducing agent feed opening in the region of the taper. The premixing chamber ensures that no deposits originating from the reducing agent can settle in the region of the mixing route. The premixing chamber is provided, in particular, for an exhaust gas purification system of a vehicle fitted with a regulated diesel catalytic converter as well as for stationary diesel engines of up to about 1000 kW (mechanical power).