A differential pressure sensor for measuring a pressure difference between two high-pressure environments is comprised of a sensor block including internal, oil-filled channels leading to an internally positioned differential pressure sensor element. Two process diaphragms are provided for transferring pressure from the high-pressure environments for isolating two distinct internal oil channels from the high-pressure environments. In order to achieve small internal oil volumes in the sensor block, additionally two separating discs, which initially separate between the two internal oil channels, are positioned in fluid communication with the high-pressure environments in order to block for the pressure from the high-pressure environments against the oil channels “from behind.” The separating discs bear against abutment faces having small openings into the internal oil channels. The separating discs are preferably given a pre-tension, and the abutment faces are then shaped correspondingly having a slightly convex shape. Preferably, separating discs with no corrugations are used.