An image reading device comprising: a document holding surface configured to hold a first document for flatbed scanning; a document conveyor unit configured to convey a second document along a conveying path for ADF-type image scanning; a first document contact surface configured to come into contact with a first side of the second document when the document conveyor unit conveys the second document; a first document pressing member disposed above the first document contact surface and configured to press the second document toward the first document contact surface when the document conveyor unit conveys the second document; a second document contact surface configured to come into contact with a second side of the second document when the document conveyor unit conveys the second document; a second document pressing member disposed below the second document contact surface and configured to press the second document toward the second document contact surface when the document conveyor unit conveys the second document; and a first reading unit including a contact image sensor and configured to: read an image on a side of the first document held by the document holding surface while traversing below the document holding surface; and read an image on the first side of the second document being conveyed by the document conveyor unit while the first reading unit is stationary below the first document contact surface; characterized by a second reading unit including a contact image sensor disposed above the second document contact surface and configured to read an image on the second side of the second document being conveyed by the document conveyor unit, wherein the second reading unit and the second document pressing member are disposed not to overlap the first reading unit and the first document pressing member when viewed from a direction perpendicular to the document holding surface, wherein at least a part of the second document pressing member is disposed lower than the document holding surface in a height direction of the image reading device that is perpendicular to a direction that the document holding surface extends. a document holding surface configured to hold a first document for flatbed scanning; a document conveyor unit configured to convey a second document along a conveying path for ADF-type image scanning; a first document contact surface configured to come into contact with a first side of the second document when the document conveyor unit conveys the second document; a first document pressing member disposed above the first document contact surface and configured to press the second document toward the first document contact surface when the document conveyor unit conveys the second document; a second document contact surface configured to come into contact with a second side of the second document when the document conveyor unit conveys the second document; a second document pressing member disposed below the second document contact surface and configured to press the second document toward the second document contact surface when the document conveyor unit conveys the second document; and a first reading unit including a contact image sensor and configured to: read an image on a side of the first document held by the document holding surface while traversing below the document holding surface; and read an image on the first side of the second document being conveyed by the document conveyor unit while the first reading unit is stationary below the first document contact surface; read an image on a side of the first document held by the document holding surface while traversing below the document holding surface; and read an image on the first side of the second document being conveyed by the document conveyor unit while the first reading unit is stationary below the first document contact surface; characterized by a second reading unit including a contact image sensor disposed above the second document contact surface and configured to read an image on the second side of the second document being conveyed by the document conveyor unit, wherein the second reading unit and the second document pressing member are disposed not to overlap the first reading unit and the first document pressing member when viewed from a direction perpendicular to the document holding surface, wherein at least a part of the second document pressing member is disposed lower than the document holding surface in a height direction of the image reading device that is perpendicular to a direction that the document holding surface extends.