An object of the present disclosure is to implement highly accurate image connecting processing between line sensors. One embodiment of the present invention is an image reading apparatus having: a plurality of line image sensors arrayed in a first direction; a conveyance unit configured to convey a document in a second direction intersecting with the first direction; a calculation unit configured to calculate a correction value for correcting a deviation at the time of connecting image data obtained by each of the plurality of line image sensors based on read data obtained by reading a chart with the plurality of line image sensors, on which a plurality of dot patterns is printed and which is conveyed by the conveyance unit; a measurement unit configured to measure an amount of conveyance in the first direction in a case where the document is conveyed in the second direction by the conveyance unit.