An intraocular lens power determination apparatus (200) for determining a highly precise IOL power, the apparatus including: an anterior segment imaging device (5) for obtaining a cross-sectional image of an anterior segment by detecting reflection from the anterior segment of an examinees eye (E) and a power calculation unit (80) obtaining an offset distance (X) from a front surface (SRI) of a lens to a point of contact (C1) of a Zinns zonule with the lens based on the anterior segment cross-sectional image obtained by the anterior segment imaging device (5) and calculating a prospective postoperative anterior chamber depth (ELP) by adding the offset distance (X) to an anterior chamber depth (ACD) of an eye so that the IOL power is calculated by using the prospective postoperative anterior chamber depth (ELP).
