Projection lens system and image projection device

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 disposed closest to a magnification side, the first lens group having positive power,
• wherein the first lens group includes one negative lens satisfying following conditions (1) and (2):
• 0.0005<Δpgfn<0.01 (1)
• 32<vdn<45 (2)
• where Δpgfn=(ngn−nfn)/(nfn−ncn)−(−2.20599×10−3×vdn+6.69612×10−1),
• vdn is Abbe number of the negative lens,
• ngn is a refractive index of the negative lens to g-line,
• nfn is a refractive index of the negative lens to F-line, and
• ncn is a refractive index of the negative lens to C-line,
• the projection lens system further comprising:
• a second lens group disposed closer to a reduction side of the first lens group, the second lens group having negative power;
• and
• a third lens group disposed closer to a reduction side of the second lens group, the third lens group having positive power,
• wherein a lens of the second lens group disposed closest to the magnification side has positive power.