An image scanner includes a light-pervious supporting plate, an enclosure, an image sensor, several light sources, and two or four light guide plates. The supporting plate supports an original to be scanned. The enclosure and the supporting plate cooperatively define a receiving space. The image sensor is received in the receiving space, and has a receiving surface. The two, four, or six light sources emit light. The light guide plates each include a light incident surface and an output surface. The light incident surface is configured for receiving light from the respective light sources. The output surface is configured for emission of surface light to scan the original on the supporting plate. In this manner, the surface light is reflected by the original to the receiving surface of the image sensor, thus an image of the original is captured.