A model simplification apparatus performs: inputting a 3D geometric model; forming a surface mesh on the input geometric model and registering the surface mesh as an initial mesh; classifying the surface mesh into partial surface meshes, and calculating feature quantities of the partial surface meshes; inputting each group of mesh elements of the geometry features as reference feature shapes; searching for groups of mesh elements of similar geometry features to the reference feature shapes. Furthermore, removing group of mesh elements corresponding to the similar feature shapes from the initial mesh, and forming simplified mesh parts instead of removed similar feature shapes.