An apparatus for generating an analytical model of an object shape model including: a detail-mesh-model generating section generating a detail mesh model of the object shape model based on the object shape model; a maximum outer shape mesh model generating section generating a maximum outer shape mesh model corresponding to an outline of the object shape model based on the object shape model; a wall-thickness-region generating section generating a basic wall-thickness region, which extends inside the maximum outer shape mesh model from at least a part of surfaces of the maximum outer shape mesh model and which has a predetermined thickness; and an overlaying section generating said analytical model by using a result of overlaying the detail mesh model with the basic wall-thickness region. Easy simplification of an analytical model can reduce time required for numerical analysis to realize an effective designing process.