A device for mixing the components of a mass flow flowing through it, provides a particularly homogeneous mixture with any desired long-term stability, even if components which are generally immiscible or can only be mixed with very great difficulty are being mixed. The device has a body (8), which it is difficult for medium to flow around, arranged in a through-flow chamber (4), this body being arranged at least partially in a part of the through-flow chamber (4) which widens in the direction of flow, so that the cavitation action and mixing action of the supercavitation field generated by the body (8) which it is difficult for medium to flow around is significantly reinforced.