An optical system includes, in order from an object side: a first lens group G1 having negative refractive power; and a second lens group G2 having positive refractive power; upon zooming from a wide-angle end state W to a telephoto end state T, a distance between the first lens group G1 and the second lens group G2 varying, and the second lens group G2 moving, and the second lens group G2 including a focusing lens group Gf that carries out focusing from an infinity object to a close object, and a decentering lens group Gs that is movable in a direction having a component perpendicular to an optical axis, thereby providing an optical system capable of establishing both of internal focusing and a decentering lens group with obtaining compactness and excellent optical performance, an optical apparatus equipped with the optical system, and a method for manufacturing the optical system.