An image processing apparatus that generates a combined image by combining plural image data acquired as a result of digitizing plural images acquired by shooting with different quantities of exposure, includes a weighting unit that adds weight to adjust proportion of combination of the image data, to at least one of the plural image data. The weighting unit includes a luminance data generating unit that combines data related to luminance of the plural image data and thus generates combined luminance data, and a weight deciding unit that decides the weight added to the image data in accordance with the combined luminance data generated by the luminance data generating unit.