A radiation image read-out apparatus comprises a read-out section for photoelectrically reading out a radiation image from silver halide film, on which the radiation image has been recorded, and thereby generating an image signal representing the radiation image. A signal conversion device converts the image signal such that distortion in the image signal, which distortion is caused to occur by nonlinear characteristics of the silver halide film, may be eliminated. A corrected image signal is thereby obtained, which can be processed commonly with an image signal obtained by reading out a radiation image from a stimulable phosphor sheet, on which the radiation image has been stored.