A variable magnification optical system includes: a positive first lens group; a negative lens group closer to an image than the first lens group; a positive lens group closer to the image than the negative lens group and including at least one lens closer to the image than an aperture stop; and a focusing group between the negative lens group and the positive lens group. When varying magnification, the first lens group moves with respect to an image plane, and distances between the first lens group and the negative lens group and between the negative lens group and the positive lens group are changed. When focusing, a distance between the focusing group and a lens facing an object-side of the focusing group is changed, and a distance between the focusing group and a lens facing an image-side of the focusing group is changed. Predetermined conditional expressions are satisfied.