1. A three-dimensional display device comprising: a three-dimensional processing unit for applying three-dimensional processing for three-dimensional display to a plurality of images having a disparity therebetween to generate a three-dimensional image; a display unit for carrying out at least three-dimensional display of the three-dimensional image; and a modifying unit for modifying, in a case where an end portion of the three-dimensional image appears to pop forward from a display surface of the display unit when the three-dimensional display is carried out, at least one of the images to modify a stereoscopic effect at least a part of the end portion so that at least the part of the end portion appears to be level with the display surface, wherein the three-dimensional processing unit applies the three-dimensional processing to the modified images, and the modifying unit sets an end portion area of a predetermined range at least a part of a periphery of the images and modifies a disparity between corresponding pixels in the end portion area of the images so that the disparity is gradually decreased toward the end of the images, and modifies at least one of the images by deforming image parts at a left area and a right area of the end portion area of a reference image serving as a reference among the images based on the disparity and modifying the image other than the reference image with the deformed image parts of the end portion area.