An image processing device includes: a horizontal parallax detecting unit that compares a standard pixel constituting a standard image with a first reference pixel located at the same height position as the standard pixel and a second reference pixel located at a height position different from the first reference pixel out of pixels constituting the reference image in the standard image and the reference image in which the same subject is drawn at horizontal positions different from each other and that detects a horizontal parallax of the standard pixel on the basis of the comparison result.