1. An image processing apparatus comprising: stereoscopic image input means for inputting a plurality of stereoscopic images, each stereoscopic image being generated by combining planar images for the right and left eyes; depth detection means for detecting a depth of each of the stereoscopic images inputted by the stereoscopic image input means, the depth being expressed as a difference between a maximum parallax and a minimum parallax in the planar images for the right and left eyes; stereoscopic image arrangement means for generating a first combined image by combining the planar images for the left eye of the plurality of stereoscopic images on a planar image in which the planar images for the left eye are laid out at least in partial overlap in such a manner that the larger depth detected by the depth detection means is, the more forward the planar image for left eye of the corresponding stereoscopic image is placed, and in the overlapped portions, a portion corresponding thereto of the image laid out more forward is displayed, and for generating a second combined image by combining the planar images for the right eye on a planar image in which the planar images for the right eye are laid out at least in partial overlap in such a manner that the larger depth detected by the depth detection means is, the more forward the planar image for right eye of the corresponding stereoscopic image is placed, and in the overlapped portions, a portion corresponding thereto of the image laid out more forward is displayed; and image recording means for recording a combined stereoscopic image constituted by the first combined image and the second combined image generated by the stereoscopic image arrangement means.