A semiconductor laser device produces a laser beam, which is adapted to be expanded into a linear laser beam for use as stimulating rays for an image read-out operation for reading out a radiation image having been stored on a stimulable phosphor sheet. The semiconductor laser device comprises a semiconductor laser chip for producing the laser beam, a package for accommodating the semiconductor laser chip therein, and a radiating window, which is fitted to the package and allows the laser beam having been produced by the semiconductor laser chip to pass therethrough. A surface of the radiating window is coated with an anti-reflection film having a reflectivity of at most 1.0% with respect to a wavelength of the laser beam having been produced by the semiconductor laser chip.