An image forming apparatus comprising: an illumination system configured to emit illuminating light beams and to irradiate an object with the illuminating light beams; an image sensor comprising photoelectric conversion sections to each of which a pixel region is allocated, which is arranged at a position where the illuminating light beams that have been transmitted through the object are incident and which is configured to capture a plurality of different images, and an image processing section configured to form a high-resolution image of the object, having a higher resolution than any of the plurality of images, based on the plurality of images, characterized in that the illumination system is configured to sequentially emit illuminating light beams from multiple different irradiation directions with respect to the object, the image sensor is configured to capture the plurality of different images in the multiple different irradiation directions, respectively, the image forming apparatus further comprises a memory configured to store data, for a subpixel region from among a plurality of subpixel regions (50a-d) included in the pixel region, the plurality of subpixel regions (50a-d) being divisions of the pixel region, about a ratio of • light rays that have passed through a subpixel region at an upper surface of the image sensor and have been incident on the photoelectric conversion section to which the pixel region is allocated to • light rays that have passed through the respective subpixel region at the upper surface of the image sensor with respect to the plurality of subpixel regions (50a-d) and each of the multiple irradiation directions, and that the image processing section is configured to form the high-resolution image of the object based on the data about said ratio that has been retrieved from the memory by multiplying the inverse matrix of a matrix having the ratio as its element by a vector of pixel values associated with the multiple different irradiation directions. an illumination system configured to emit illuminating light beams and to irradiate an object with the illuminating light beams; an image sensor comprising photoelectric conversion sections to each of which a pixel region is allocated, which is arranged at a position where the illuminating light beams that have been transmitted through the object are incident and which is configured to capture a plurality of different images, and an image processing section configured to form a high-resolution image of the object, having a higher resolution than any of the plurality of images, based on the plurality of images, characterized in that the illumination system is configured to sequentially emit illuminating light beams from multiple different irradiation directions with respect to the object, the image sensor is configured to capture the plurality of different images in the multiple different irradiation directions, respectively, the image forming apparatus further comprises a memory configured to store data, for a subpixel region from among a plurality of subpixel regions (50a-d) included in the pixel region, the plurality of subpixel regions (50a-d) being divisions of the pixel region, about a ratio of • light rays that have passed through a subpixel region at an upper surface of the image sensor and have been incident on the photoelectric conversion section to which the pixel region is allocated to • light rays that have passed through the respective subpixel region at the upper surface of the image sensor • light rays that have passed through a subpixel region at an upper surface of the image sensor and have been incident on the photoelectric conversion section to which the pixel region is allocated to • light rays that have passed through the respective subpixel region at the upper surface of the image sensor with respect to the plurality of subpixel regions (50a-d) and each of the multiple irradiation directions, and that the image processing section is configured to form the high-resolution image of the object based on the data about said ratio that has been retrieved from the memory by multiplying the inverse matrix of a matrix having the ratio as its element by a vector of pixel values associated with the multiple different irradiation directions.