PURPOSE: To facilitate the enhancement of the accuracy relating to a positional relation between plural pieces of fθ lenses, inclination, angle of inclination relations, etc., by integrally molding these fθ lenses of plastic as a lens body and to improve the assembling property thereof.

CONSTITUTION: Plural pieces, 2 pieces in such a case, the fθ lenses 16, 17 are integrally molded of the plastic as the lens body 22. The accuracy in the relative positional relation between the fθ lenses 16 and 17 for this purpose is easily enhanced to order of ≤100μm. There is no need for discretely assembling the respective fθ lenses 16, 17 and the assembly is facilitated. Further, the molding cost is saved and the production at a low cost is possible. A first cylindrical lens 13 and the fθ lenses 16, 17 may be integrally molded of the plastic as the lens body 23 or the fθ lenses 16, 17 and a second cylindrical lens 18 may be integrally molded of the plastic as the lens body 24.