Provided are an ion beam control apparatus and a control method for controlling an ion beam energy expansion level and an ion beam size in a radial direction. An ion beam control apparatus Sa is provided with an ion beam generating unit 2, and an ion beam control unit 1a in which a generated ion beam (IB) is input and controlled to be output with the prescribed level of energy expansion and the prescribed diameter in the radial direction. In the ion beam control unit 1a, phase rotation by a radio frequency electric field that increases existing probability with the prescribed level of energy is at least used.