This invention aims to create a three-dimensional model of satisfactory accuracy even when adopting a method of performing three-dimensional measurement by arbitrarily changing a positional relationship between an actual model and a camera, and aligning and integrating three-dimensional information restored by each measurement. A polygonal mark M having a shape in which a direction can be uniquely specified is attached to a predetermined area of an actual model WM of a work to be three-dimensionally recognized. A process of changing the orientation of the actual model WM such that a state in which the mark M is contained in the view of each camera is maintained, and then performing the three-dimensional measurement is executed over a plurality of times. A predetermined number of, or two or more pieces of three-dimensional information is selected from the three-dimensional information restored by each measurement, these pieces of three-dimensional information are aligned and integrated, the information corresponding to the mark is deleted or invalidated from the integrated three-dimensional information, and the three-dimensional information after such a process is set as a three-dimensional model.