An image reading apparatus to read a sheet being conveyed includes a memory and a reading device to read one side of the sheet in units of a line area orthogonal to a conveyance direction of the sheet. A read image of a first region corresponding to a leading edge side of the sheet in the conveyance direction is stored into the memory. A read image of a second region subsequent to the first region is not stored. A read image of a third region subsequent to the second region and corresponding to a trailing edge side of the sheet in the conveyance direction is stored in the memory. Each read image is an image read by the reading device. Predetermined processing is performed based on the read image of the first region and the read image of the third region stored in the memory.