In short, the image processing device for obtaining a single image by using a plurality of image-pickup elements comprises a plurality of image-pickup signal processing circuits that are provided for each of the image-pickup elements, an image arrangement conversion circuit which converts the read-out order of the images corresponding to the respective image-pickup elements that are output from the image-pickup signal processing circuits, an image splitting processing circuit for performing image splitting on the image that is output from the image arrangement conversion circuit, an image processing circuit for performing image processing in parallel on each of the split images, and an image compression circuit for compressing in parallel each of the split images that are output from the image processing circuit.