A relative pressure measuring transmitter resistant to the intrusion of moisture. includes a housing, an insert arranged in the housing, a gap existing between the housing and the insert, a relative pressure sensor, and, connected to the relative pressure sensor, a reference pressure supply line, which leads into the insert, opens on an outer wall of the insert, and has an interior, which is connected via an opening in insert with the gap The housing has a bore passing through it, via which the gap is placed in communication with an environment of the relative pressure measuring transmitter.