1. A three-dimensional CAD model creating apparatus comprising: a table creating unit that creates, for a three-dimensional CAD model, tabular data that describes change logic for each changed state, the change logic associating a changed state with a condition to be satisfied to shift to the changed state, the changed state being a form after transformation of the three-dimensional CAD model; a data converting unit that converts each change logic set in the created tabular data into a description in a certain program language, and creates a model built-in program; an model built-in program IO unit that registers the converted model built-in program to the three-dimensional CAD model; and a three-dimensional CAD software-program unit that transforms the three-dimensional CAD model when receiving an operation for transforming the three-dimensional CAD model, based on the operation and a change logic described in a model built-in program registered to the three-dimensional CAD model.