A zoom lens system according to the disclosure, in order from an object side to an image side, includes a first lens group with positive optical power, a second lens group with negative optical power, and a subsequent lens group composed of at least three lens groups. During zooming operation, the first lens group moves along the optical axis and the second lens group does not move. The second lens group has an aperture stop. The second lens group satisfies following condition (1), −9.0≤fG1/fG2≤−2.0   (1) where fG1 is the focal length of the first lens group, and fG2 is the focal length of the second lens group.