1. A texture mapping method comprising the steps of: extracting a boundary between a texture portion and a background portion for each of the texture images; weighting segments obtained by segmentalizing the texture portion correlatively with a distance from the boundary using the boundary information obtained by the extraction of the boundary; calculating a mapping value of an overlapped portion of the plural texture images by means of weighted average; and mapping texture portions of the plural texture images on the surface of the three-dimensional model using the calculated mapping value.