1. An apparatus for generating a three-dimensional model of an object, comprising: a storage unit that stores three-dimensional coordinates (X,Y,Z) of a plurality of vertices on a standard model of the object; an image input unit that inputs a plurality of input images acquired by photographing the object; a first detection unit that detects a coordinate (x,y) of a first point corresponding to a vertex on the standard model, from a first image selected from among the plurality of input images; a second detection unit that detects a coordinate (x′,y′) of a second point corresponding to the coordinate of the first point on the first image, from a second image other than the first image, input by the image input unit; a depth computation unit that computes a depth of the first point on the first image by using the coordinate (x,y) of the first point on the first image and the coordinate (x′,y′) of the second point on the second image; and a first update unit that updates the three-dimensional coordinate (X,Y,Z) on the standard model based on the coordinate (x,y) of the first point on the first image and the depth calculated by the depth computation unit.