In a first route, image data from an image reading unit is processed by both a first image processing block and a second image processing block and sent to a storage unit, and in a second route, the image data processed by the first image processing block is stored in the storage unit and image data from the storage unit is processed by the second image processing block and sent to the storage unit. The control unit switches a process of the second image processing block according to a result of a process of the first image processing block, and switches an input source to the second image processing block according to a process content of the second image processing block.