Comprising, in order from an object side: a first lens group G1 having positive refractive power; a second lens group G2 having negative refractive power; an aperture stop S; a third lens group G3 having positive refractive power; and a fourth lens group G4 having positive refractive power; upon zooming from a wide-angle end state to a telephoto end state, the distance between the first lens group G1 and the second lens group G2, the distance between the second lens group G2 and the aperture stop S, the distance between the aperture stop S and the third lens group G3, and the distance between the third lens group G3 and the fourth lens group G4 being varied, and the distance between the aperture stop S and the fourth lens group G4 being constant; and a predetermined conditional expression being satisfied, thereby providing a variable magnification optical system which is compact in size and has a high variable magnification ratio and high optical performance, an optical apparatus, and a method for manufacturing a variable magnification optical system.