1. A three-dimensional image processing apparatus that performs an image correction process, the apparatus comprising: a left eye image and a right eye image contained in a three-dimensional image obtained using a dual-lens technique or a multiple-viewpoint technique; an end part region detector configured to detect as an end part region both: a region including an edge on a left side of a subject contained in the left eye image and the right eye image, and a region including an edge on a right side of the subject contained in the left eye image and the right eye image; and an edge correction unit configured to execute a smoothing process on a region in the end part region of the subject detected by the end part region detector wherein: the end part region detector is further configured to detect the region including an edge on the left side of the subject as the left end part region and detect the region including an edge on the right side of the subject as the right end part region; and the edge correction unit is further configured to execute: a smoothing process on the left end part region in the left eye image at a first strength, and execute a smoothing process on the right end part region in the left eye image at a second strength that is a lower strength than the first strength; and a smoothing process on the right end part region in the right eye image at a third strength, and executes a smoothing process on the left end part region in the right eye image at a fourth strength that is a lower strength than the third strength.