<p>An image reading device according to one aspect of the invention comprises: a conveying unit configured to convey a recording medium; a first transmissive portion having a first surface that allows the recording medium to pass through the first surface; a second transmissive portion having a second surface on which a recording medium is allowed to be placed; an image reading unit comprising a line sensor extending in a first direction and movable on a second path, the second path continuously extending below the first transmissive portion and the second transmissive portion; and a driver configured to move the image reading unit on the second path. A relative distance of a third direction perpendicular to the first and second directions between the line sensor and the first surface changes in the second path below the first transmissive portion.</p>
