The present invention provides a control method of an image reading device, an image reading device, and a non-transitory computer-readable medium having a program stored thereon, which avoid a reduction in reading resolution. The control method of the image reading device includes: a first step (ST101) of generating N line-shaped images indicating N line-shaped regions (W11) in an imaging target (T1) being conveyed in a conveying direction (X1) by imaging the N line-shaped regions (W11) extending in a direction perpendicular to the conveying direction (X1); a second step (ST102) of performing the same step as the first step (ST101) at a point in time when the imaging target (T1) is conveyed by an amount associated to a width (11a) of N−1 line-shaped regions; and a step (ST103) of generating a read image by arranging the N line-shaped images generated in each of the steps in ascending order.