The image reading device includes: a reading unit that includes a light source emitting light to irradiate an image on a recording medium transported in a first direction and a light receiving portion that receives light reflected by the recording medium; a transport path forming unit that forms a part of a transport path for the recording medium; a light transmitting portion that is provided in the transport path forming unit and transmits the light; and plural projection members that are provided to the light transmitting portion so as to project from the light transmitting portion toward the transport path, and that are arranged in a second direction crossing the first direction while each extending in the first direction.