To perform data processing such as shading in a short time.

This three-dimensional CAD device is equipped with a reference component data storage part 10 stored with pieces of reference component data which can be displayed and can not be edited, an actual component data storage part 11 stored with actual component data which can be displayed and edited, a copy part 12 which copies the pieces of reference component data in the reference component data storage part 10 and the actual component data in the actual component data storage part 11 to generate one piece of composite component data, a shading process part 13 which generates shading data by shading the composite component data generated by the copy part 12 at a time, and a monitor 14 which displays the shading data generated by the shading process part 13.