An apparatus 1 for generating three-dimensional model data is provided with: two CCD cameras 13 and 14 for imaging an attached object attached to a machine tool to generate two-dimensional image data; a first model-data storing section 19 for storing model data of the attached object, a second model-data storing section 21 for storing the model data related to at least a part of the machine tool; an edge detecting section 17 for detecting edges; a shape-feature recognizing section 18 for recognizing a shape feature; an object recognizing section 20 for recognizing the model data of the attached object imparted with the recognized shape feature; and a model-data generating section 22 for generating three-dimensional model data including the attached object and a part of the machine tool.