Provided are an image processing apparatus, a control method, and a control program to more accurately remove the shading from the image including the shading. An image processing apparatus includes a storage device to store a shading pattern in which a condition of gradation values of a target pixel and a plurality of pixels having a predetermined positional relationship with respect to the target pixel are set, an acquisition module to acquire a multiple value image, a binary image generation module to generate a binary image from the multiple value image, a detection module to detect a pixel satisfying the condition set in the shading pattern from the multiple value image as a part of a shading, a shading removal pattern generation module to generate a shading removal pattern for removing the detected shading, based on the multiple value image, a shading removal image generation module to generate a shading removal image by applying the shading removal pattern to the binary image, and an output device to output the shading removal image or information generated using the shading removal image.