The image scanning apparatus includes a light source including at least one light emitting diode (LED) to irradiate light to a document which is a scan target, a light source control unit to control a lighting-up point of time of the light source, an image sensor to transform an image formed by light reflected from the document into an electric signal according to a result of controlling the lighting-up point of time, and an output unit to output image data corresponding to the transformed electric signal.