1. An image processing device comprising: a reference image selector configured to select one image of an image group as a reference image, the image group including four or more images generated in such a manner that an object is sequentially captured separately in four or more different wavelength bands; a processing target image selector configured to select, as a processing target image, each of a plurality of images of the image group other than the reference image; an arrangement order setting unit configured to set arrangement order of the images included in the image group such that at least the wavelength bands at the time of capturing the images or positions in capturing order are adjacent to each other between the adjacent images; a conversion information estimation unit configured to estimate conversion information between the images adjacent to each other when the images included in the image group are arrayed in the arrangement order; a deformed image creation unit configured to create a deformed image by subjecting the processing target image to an image conversion using the conversion information cumulatively from the processing target image to the reference image in the arrangement order; and a color image creation unit configured to create a color image using a plurality of the deformed images created based on the respective plurality of images and the reference image.