The invention relates to a high-pressure mercury vapor lamp suitable for sterilization purposes. The high-pressure mercury vapor lamp according to the invention is remarkable in that germanium and oxygen are added in small quantities to the mercury and/or the mercury halides. The addition of germanium monoxide furthermore surprisingly increases the GAC efficiency (GAC: short for Germicidal Action Curve) of a high-pressure mercury vapor lamp, because germanium monoxide emits a strong molecular band system in the range from 250 to 280 nm. The germicidal action of the high-pressure mercury vapor lamp according to the invention is thus increased with respect to that of conventional highpressure mercury vapor lamps. This is apparent from the fact that the GAC-weighted radiant flux is greater than before in the high-pressure mercury vapor lamp according to the invention.