To obtain increase in the speed in processing as a whole, when achieving three-dimensional display.

A three-dimensional image processor 100 generates a common view volume for including a view volume determined by each of actual cameras, based on one tentative camera arranged in a virtual three-dimensional space. Then, the processor 100 performs distortion conversion to the common view volume and acquires the view volume for each actual camera. Finally, two view volumes, acquired for each actual camera, are projected onto a projection surface, thus generating a two-dimensional image having parallax. In this manner, a two-dimensional image that serve as the base station of a parallax image can be obtained simply by the tentative camera, by acquiring the view volume for each regular camera from the common view volume, thus saving processings of actually arranging the regular camera and speeding up the processing as a whole.