1. An endoscope apparatus comprising: an electronic endoscope for capturing a measurement object and producing a picked-up image signal; an image-processing unit for producing an image signal based on the picked-up image signal; and a measurement processing unit for conducting a measurement processing on the measurement object based on the image signal, wherein the measurement processing unit comprises: a reference point-designating unit for designating two reference points on the measurement object; a loss-composing points-calculating unit for calculating loss-composing points that constitute a loss outline formed on the measurement object based on the two reference points; a loss-measurement unit for measuring a loss size based on the loss-composing points; and an approximate-outline-calculating unit for calculating two approximate outlines calculated by approximating an outline of the measurement object based on the two reference points; wherein the loss-composing points-calculating unit calculates the loss-composing points based on the two reference points and the two approximate outlines; and wherein the reference point-designating unit designates end points as the two reference points on cross-points between the outline of the measurement object and the loss outline.