A device for recording the resistance inhomogeneity in high-resistivity and photosensitive semiconductor plates of large diameter is described. A measurement of homogeneity is realized by recording the spatial distribution of the gas discharge glow intensity between two transparent electrodes with the plate between them. Plates of GaAs with resistivity of 10(6)-10(8) Omega cm, thickness from 0.3 to 1.5 mm and the diameter from 20 to 60 mm have been studied. A gas discharge gap was formed by dielectric separator with thickness from 20 to 80 mu m. A discharge has been realized in air at a pressure from 60 to 600 Torr. The possibilities of the proposed device have been evaluated, i.e. a relative change of the resistance inhomogeneity is determined by a relative change of discharge glow intensity the resolution of which is determined by method of its recording. Semiconductor plates with the resistivity from 10(5) to 10(9) Omega cm can be used in the device proposed.