An image processing device comprising: a plurality of filtering units (11, 12, 51, 52, 61 - 67) configured to perform predetermined filter processing on each of a plurality of captured images including a first captured image and a second captured image respectively including outputs from a first pixel and a second pixel of a plurality of pixels, the first pixel and the second pixel having different sensitivities, wherein the plurality of pixels is arranged on a pixel array; a synthesis rate calculation unit configured to calculate a synthesis rate by using at least one of the filter processing results provided by the plurality of filtering units (11, 12, 51, 52, 61 - 67); a plurality of shading correction units (13, 14) configured to perform shading correction processing respectively on the first and second captured images of the plurality of captured images; a moving subject detection unit configured to detect a moving subject on the basis of a difference of results of multiplying each of the filter processing results provided by the plurality of filtering units (11, 12, 51, 52, 61 - 67) with respective gains corresponding to positions in the first and second captured images at the time of performing the shading correction processing on the corresponding captured image by the plurality of shading correction units; a synthesis rate control unit configured to control the application of the calculated synthesis rate on the basis of the detection result of the moving subject detection; and a synthesis unit configured to synthesize the shading processing results provided by the plurality of shading correction units (13, 14) according to the controlled synthesis rate for forming a wider dynamic range image. a plurality of filtering units (11, 12, 51, 52, 61 - 67) configured to perform predetermined filter processing on each of a plurality of captured images including a first captured image and a second captured image respectively including outputs from a first pixel and a second pixel of a plurality of pixels, the first pixel and the second pixel having different sensitivities, wherein the plurality of pixels is arranged on a pixel array; a synthesis rate calculation unit configured to calculate a synthesis rate by using at least one of the filter processing results provided by the plurality of filtering units (11, 12, 51, 52, 61 - 67); a plurality of shading correction units (13, 14) configured to perform shading correction processing respectively on the first and second captured images of the plurality of captured images; a moving subject detection unit configured to detect a moving subject on the basis of a difference of results of multiplying each of the filter processing results provided by the plurality of filtering units (11, 12, 51, 52, 61 - 67) with respective gains corresponding to positions in the first and second captured images at the time of performing the shading correction processing on the corresponding captured image by the plurality of shading correction units; a synthesis rate control unit configured to control the application of the calculated synthesis rate on the basis of the detection result of the moving subject detection; and a synthesis unit configured to synthesize the shading processing results provided by the plurality of shading correction units (13, 14) according to the controlled synthesis rate for forming a wider dynamic range image.