A projection lens system that has a compact configuration and is capable of correcting a color aberration. In the system, first and second lenses have a weak refractive power, respectively, and a third lens has a strong positive refractive power. A fourth lens corrects an aberration generated by the third lens, and a fifth lens has a negative refractive power. A diffractive optical element is formed on at least one among the surface of the first to fifth lenses. A color aberration and spherical aberration is corrected with the diffractive optical element, so that a high resolution can be realized without increasing the number of lenses and the manufacturing cost can be reduced.