1. An image reading device comprising: a camera that shoots a shooting target from a position facing the shooting target and outputs a shot image as a two-dimensional image; a light source unit that, at least when the shooting target is a bound document, sequentially irradiates the bound document with light from a first irradiation position and from a second irradiation position opposing each other with respect to a first straight line, which is in a plane of the document, and which is orthogonal to a direction of a binding portion of the document, the first straight line dividing the shooting target into an upper portion which includes the first irradiation position, and a lower portion which includes the second radiation position; a shooting controller that controls the camera to shoot a first region positioned at the second irradiation position side on the document when the light source unit irradiates the document with light from the first irradiation position and the light is regularly reflected by the document at the first irradiation position side, and controls the camera to shoot a second region containing a region other than the first region on the document when the light source unit irradiates the document with light from the second irradiation position and the light is regularly reflected by the document at the second irradiation position side; and a processor that combines a two-dimensional image obtained by the camera shooting the first region and a two-dimensional image obtained by the camera shooting the second region to generate an image of the entire document.