A structural analysis apparatus automatically sets a boundary between an entire model and a detailed model to thereby obtain a highly accurate solution without intervention by an operator and with fewer man-hours and shorter calculation time. An iso-surface creation step creates a field iso-surface from an analysis result of a mesh model. A detailed mesh model creation step uses the field iso-surface created by the iso-surface creation step to create a detailed mesh model of a part of the mesh model. An analysis step uses the analysis result of the mesh model to perform analysis of the detailed mesh model created by the detailed mesh model creation step. An analysis evaluation step evaluates the analysis result of the detailed mesh model based on the analysis result obtained by the analysis step and analysis result of the mesh model.