An ion implantation apparatus includes an implantation part, a measuring part, and a controller. The ion implantation part implants ions into an implantation region located at a bottom of a concave portion provided on a semiconductor substrate. The measuring part measures an implantation amount of ions corresponding to an aspect ratio of the concave portion based on ions implanted from the implantation part thereinto, at a first position at which the semiconductor substrate is arranged when the ions are implanted into the implantation region or a second position close to the first position. The controller controls the implantation part to stop implantation of the ions into the measuring part when an accumulated amount of the implantation amount has reached a predetermined amount according to a target accumulation amount of the implantation region.