In an image reader, if a first and second light sources alternately light-up when a conveying unit conveys an imaging target medium, a visible light data group that is based on a reflected light, of a wavelength inside a visible spectrum, of a first light having a wavelength inside the visible spectrum and a visible light external data group that is based on the reflected light, of the wavelength inside the visible spectrum, of a second light having a wavelength outside the visible spectrum are alternately generated. By scanning the imaging target medium once and by collecting multiple visible light data group, first image data of the imaging target medium, based on the first light, is generated. Furthermore, by collecting multiple visible light external data group, second image data of the imaging target medium, based on the second light, is also generated.