An image scanning apparatus comprises: a first image scanning unit that performs image scanning of a first surface of an original; a second image scanning unit that performs image scanning of a second surface of the original; and a control unit that controls output channels for outputting analog signals from the first image scanning unit, wherein the control unit changes, between a case of single-sided scanning and a case of both-sided scanning, the output channels of the analog signals output from a part of scanning region in a plurality of scanning regions of the first image scanning unit, and changes, between a case of single-sided scanning and a case of both-sided scanning, the number of output channels for outputting the analog signals from the first image scanning unit.