1. An image processing device comprising: an image data acquisition unit that acquires, via an optical system, image data including a luminance component and a color difference component; a shading detection unit that detects shading of the luminance component included in the image data and detects shading of the color difference component; a luminance shading correction coefficient calculation unit that, on the basis of the shading of the luminance component detected by the shading detection unit, calculates a luminance shading correction coefficient that is for correcting the shading of the luminance component; a color difference shading correction coefficient calculation unit that, on the basis of the shading of the color difference component detected by the shading detection unit, calculates a color difference shading correction coefficient that is for correcting the shading of the color difference component; a conversion unit that converts the color difference shading correction coefficient calculated by the color difference shading correction coefficient calculation unit so as to be at a predetermined ratio with respect to the luminance shading correction coefficient calculated by the luminance shading correction coefficient calculation unit; a first acquisition control unit that controls the image data acquisition unit so as to acquire a plurality of sets of image data while altering an exposure condition; a first correction unit that corrects the images acquired by the first acquisition control unit on the basis of the color difference shading correction coefficient converted by the conversion unit; and a pixel addition unit that performs pixel addition of the images corrected by the first correction unit.