1. An image processing apparatus which generates a first synthetic image and a second synthetic image used for displaying a stereoscopic synthetic image and having disparity with respect to each other, on the basis of a plurality of captured images obtained by capturing with imaging means while moving the imaging means, comprising: a first synthetic image generating means for generating the first synthetic image by synthesizing each of images in a first strip region of the captured images; a second synthetic image generating means for generating the second synthetic image by synthesizing each of images in a second strip region of the captured images which is different from the first strip region; and disparity controlling means for adjusting the disparity of the first synthetic image and the second synthetic image, by shifting at least one of the first synthetic image and the second synthetic image on the basis of a predetermined amount of shift.