A vertical profile, a horizontal profile, and an integrated current value of an ion beam are measured by a plurality of stationary beam measuring instruments and a movable or stationary beam measuring device. At a beam current adjustment stage before ion implantation, a control device simultaneously performs at least one of adjustment of a beam current to a preset value of the beam current, adjustment of a horizontal beam size that is necessary to secure uniformity of the horizontal ion beam density, and adjustment of a vertical beam size that is necessary to secure the uniformity of the vertical ion implantation distribution on the basis of a measurement value of the stationary beam measuring instruments and the movable or stationary beam measuring device.