In an image reading apparatus, it is judged whether an original sheet is either one of a first sheet type, whose sheet length is longer than or equal to a first conveyance distance and shorter than a second conveyance distance, and a second sheet type, whose sheet length is longer than or equal to the second conveyance path, the first conveyance distance being distance between a first conveyance roller and a second conveyance roller, the second conveyance distance being distance between a supply roller and the second conveyance roller. The original sheet is conveyed at a separation timing, when the original sheet separates away from the supply roller, at a speed that is smaller for a case where the original sheet is of the first sheet type than for a case where the original sheet is of the second sheet type. An image is read from the conveyed original sheet.