An image reading device that efficiently performs shading correction that flexibly responds to changes in the diffusion properties of reflected light on the surface of a reading target efficiently performing same as a result of including: controlling a plurality of light sources so as to cause only a specific light source among the light sources to be lit; obtaining the diffusion state of a first reflected light generated by the specific light source being lit, in a state in which general shading correction data not dependent on the image reading target is generated; obtaining a diffusion state for a second reflected light generated by light being irradiated on to the reading target by the specific light source; and generating dedicated shading correction data that relies on the reading target, based on the first reflected light diffusion state, the second reflected light diffusion state, and the general shading correction data.