A device for mixing two paste like compounds, such as a dental molding compound using a catalyst for the acceleration of polymerization. The housing has a mixing area with at least two inlet openings for the compounds and an outlet opening for the mixed compound. The device also has a mixing element that is disposed in the mixing area and propelled around a longitudinal axis. The housing has a coupling section that is situated in front of the mixing area with two coupling openings for connecting with two dispensing openings of a device for dispensing the two paste like compounds. The first and second ducts connect to the couplings via the coupling openings extending through the coupling section into the inlet openings for the mixing area. The two ducts are formed so that the first duct requires a greater time of entry of the compound into the mixing area than the time required for the second compound flowing through the second duct.