A three-dimensional (3D) structure data creation technique capable of readily creating 3D structure data is disclosed. This method is for producing data of a 3D structure which is made up of a plurality of elements. The method includes the steps of preparing first and second two-dimensional (2D) sectional images different in normal vector from each other, forming first and second unit graphics based on these 2D images, partitioning each unit graphic on a per-element basis, performing layout arrangement of two unit graphics in accordance with normal vectors, expanding these unit graphics for conversion to 3D objects, and allocating a selected element to a region in which elements of the unit graphics failing to coincide with each other, which region is included in and specified from those regions with intersection of respective partitioned parts of the unit graphics, thereby to create the 3D structure data required.