A zoom lens system includes a first lens group having a positive power, a second lens group that has a negative power and includes one lens element, a third lens group that has a positive power and includes at least two lens elements, and a subsequent lens group that has a positive power as a whole and includes at least two lens groups in order from an object side to an image side. In zooming operation, at least the first lens group to the third lens group move along an optical axis, and a condition of −9.0