An ion implantation apparatus includes a beam scanner that provides reciprocating beam scanning in a beam scanning direction, a beam measurer that measures a beam current intensity distribution in the beam scanning direction at a downstream of the beam scanner, and a controller. The controller includes a scanning waveform preparing unit that determines whether or not a measured beam current intensity distribution measured by the beam measurer with use of a given scanning waveform fits a target non-uniform dose amount distribution, and that, in a case of fitting, correlates the given scanning waveform with the target non-uniform dose amount distribution.