There is described an image-reading apparatus to acquire image data by reading a scanned image comprising an image sensor having a light emitting means and a photo receiving means for receiving a light emitted from the light emitting means, and a reading control means for controlling the image sensor. The photo receiving means separately acquires light amount data in a plurality of wavelength regions, and the reading control means independently controls a start and a stop of each of light receiving operations of the photo receiving means conducted in the plurality of wavelength regions. Further, there is also described an image-reading apparatus to acquire image data by reading a scanned image comprising an image sensor having a plurality of light emitting means, light emitting wavelength regions of which are different from each other, and photo receiving means for receiving light emitted from the plurality of light emitting means, and a reading control means for controlling the image sensor, and the reading control means independently controls a start and a stop of each of light emitting operations conducted by the plurality of light emitting means.