Because horizontal boom motion of a rotary crane generates two-dimensional load-sway, skilled labor is required to control the rotary crane, and automatic control system that achieves boom positioning and load-sway suppression simultaneously has been widely studied thus far. Although vertical and horizontal boom motion is employed for the load-sway suppression in most existing studies, it seems undesirable to use the vertical boom motion only for load-sway suppression from the viewpoint of safety and energy saving, because it is against the gravity. In this paper, we present a nonlinear controller design that enables to achieve both boom positioning and load-sway suppression using only horizontal boom motion. Simulation results demonstrate the effectiveness of the proposed method.