An image reading device includes first and second image reading platforms that are separated from each other with a separation member, an image reading element movable between positions facing the first and second image reading platforms, a pair of sliding members that is slideable in a direction according to the movement of the image reading element on a pair of sliding paths that extends in the direction and is disposed so as to be spaced apart from each other in another direction intersecting with the direction and that is provided so as to at least partially overlap with the first and second image reading platforms; and a pair of protrusions disposed on parts of the pair of sliding paths positioned on both sides of the separation member in the another direction and that protrudes further toward the pair of sliding members from the first and second image reading platforms.

An image reading apparatus includes a reader that reads an image of a document by using plural light receiving elements arranged in a first scanning direction; a moving unit that moves the reader in a second scanning direction to move a reading position at which the reader reads the document; and an adjusting unit that moves the reader in the first scanning direction to adjust a position of the reader in the first scanning direction.

An image reading apparatus includes a carriage, a drive mechanism, an imaging device, a controller, and a first white reference plate. The controller controls the drive mechanism, thereby moving the carriage to a search start position, located on a side of a document setting region with respect to a region occupied by the first white reference plate, decides, on a basis of image data on an outer side of the document setting region in the main scanning direction, sequentially read by the imaging device while the carriage is being moved in a first direction, from the search start position toward the region occupied by the first white reference plate, whether a read image is white, and positions the carriage at a home position, by moving the carriage from a position thereof when the read image was decided as white, by a predetermined distance in the first direction.