A hot cathode ionization pressure gauge with the following electrodes, arged at a distance from one another in the specified sequence along an axis:(a) a thermionic cathode filament which has a central active part and lateral support parts;(b) an essentially flat, diaphragm-like control electrode,(c) an essentially flat apertured acceleration electrode and(d) an essentially flat ion collector electrode,(e) a base plate on which the filament, the control electrode, the acceleration electrode and ion collector electrode are mounted,wherein the base plate consists of a ceramic material and has a plurality of through holes, and each of said control, acceleration and ion collector electrodes comprises a support member having essentially a shape of an inverted "U" with first and second legs, one of said legs of each electrode support member extending through a corresponding hole of said base plate and being fixed therein.