A light beam scanning device includes a light source section, a deflector and a reflection type optical system. The light source section is provided with three laser light sources. These laser light sources utilizes different modulation systems depending on corresponding semiconductor lasers. That is, the red-light laser light source and the blue-light laser light source each utilize a direct modulation system and the green-light laser light source utilizes an external modulation system using an external modulator (AOD). Reflecting mirrors and, the deflector and an arcsine mirror, which form the reflection type optical system, are arranged sequentially along an optical path at the side of the light source section from which light is emitted. Accordingly, laser light emitted from the light source section is guided only by the reflection type optical system to a recording material. As a result, no correction for light beams of different wavelengths is required.