A sanitary single-lever mixer comprising a housing, known per se, having a receiving compartment which is open towards the top. The housing is associated with a closing part which covers the upper opening of the receiving compartment and comprises a center passage. The adjusting lever or the handle extends through said passage. The closing part has a convex, spherical top when seen from above. The handle is associated with a cover element that has an outer exposed part with an exposed surface and a sliding element connected to the exposed part.