The invention relates to a device and a method for producing nanoparticles, in which method starting materials for nanoparticles are mixed at least as liquid droplets and optionally also as gases and/or vapours with at least combustion gases in a premixing chamber and the mixture is separated for liquid drops larger than size d, whereafter the mixture is conducted to at least one burner, in which the combustion gases are ignited such that a heavily mixing flame is generated, in which the starting materials react and optional solvents evaporate and generate through nucleation and/or sintering and/or agglomeration particles having a diameter of 1 to 1000 micrometres.