A high-energy ion implanter includes: a beam generation unit that includes an ion source and a mass analyzer; a high-energy multi-stage linear acceleration unit that accelerates an ion beam so as to generate a high-energy ion beam; a high-energy beam deflection unit that changes the direction of the high-energy ion beam toward the wafer; and a beam transportation unit that transports the deflected high-energy ion beam to the wafer. The deflection unit is configured by a plurality of deflection electromagnets, and at least a horizontal focusing element is inserted between the plurality of deflection electromagnets.