A projection lens system comprising a plurality of lens groups, the plurality of lens groups each including one or more lenses and moving such that an interval between the lens groups changes during a zooming action, the projection lens system comprising a first lens group (G1) disposed closest to a magnification side, the first lens group (G1) having positive power, a second lens group (G2) disposed closer to a reduction side of the first lens group, the second lens group (G2) having negative power, a third lens group (G3) disposed closer to a reduction side of the second lens group (G2), the third lens group (G3) having positive power, and an aperture diaphragm (A) being disposed between the second lens group (G2) and the third lens group (G3), wherein the first lens group (G1) includes one negative lens (L1) satisfying following conditions and : 0.0005 < Δ pgfn < 0.01 32 < vdn < 45 where Δ pfgn = ngn − nfn / nfn − ncn − − 2.20599 × 10 − 3 × vdn + 6.69612 × 10 − 1 , vdn is Abbe number of the negative lens (L1), ngn is a refractive index of the negative lens (L1) to g-line, nfn is a refractive index of the negative lens (L1) to F-line, and ncn is a refractive index of the negative lens (L1) to C-line, wherein when the projection system zooms from a wide angle end to a telephoto end, the first lens group (G1) is relatively fixed with respect to an image plane of an original image (S), the second lens group (G2) moves toward the reduction side with respect to the image plane of the original image (S) and the third lens group (G3) moves toward the magnification side with respect to the image plane of the original image (S). the projection lens system comprising a first lens group (G1) disposed closest to a magnification side, the first lens group (G1) having positive power, a second lens group (G2) disposed closer to a reduction side of the first lens group, the second lens group (G2) having negative power, a third lens group (G3) disposed closer to a reduction side of the second lens group (G2), the third lens group (G3) having positive power, and an aperture diaphragm (A) being disposed between the second lens group (G2) and the third lens group (G3), wherein the first lens group (G1) includes one negative lens (L1) satisfying following conditions and : 0.0005 < Δ pgfn < 0.01 32 < vdn < 45 where Δ pfgn = ngn − nfn / nfn − ncn − − 2.20599 × 10 − 3 × vdn + 6.69612 × 10 − 1 , vdn is Abbe number of the negative lens (L1), ngn is a refractive index of the negative lens (L1) to g-line, nfn is a refractive index of the negative lens (L1) to F-line, and ncn is a refractive index of the negative lens (L1) to C-line, wherein when the projection system zooms from a wide angle end to a telephoto end, the first lens group (G1) is relatively fixed with respect to an image plane of an original image (S), the second lens group (G2) moves toward the reduction side with respect to the image plane of the original image (S) and the third lens group (G3) moves toward the magnification side with respect to the image plane of the original image (S). vdn is Abbe number of the negative lens (L1), ngn is a refractive index of the negative lens (L1) to g-line, nfn is a refractive index of the negative lens (L1) to F-line, and ncn is a refractive index of the negative lens (L1) to C-line, wherein when the projection system zooms from a wide angle end to a telephoto end, the first lens group (G1) is relatively fixed with respect to an image plane of an original image (S), the second lens group (G2) moves toward the reduction side with respect to the image plane of the original image (S) and the third lens group (G3) moves toward the magnification side with respect to the image plane of the original image (S). <EOS>