Some embodiments of the present disclosure provide a Contact Image Sensor (CIS), including a light source, a lens, a light-sensing portion receiving light converged by the lens, a sensor substrate carrying photosensitive Integrated Circuits (IC) arranged linearly, a frame accommodating the lens and the sensor substrate, and a light-transmitting plate provided on an upper part of the frame and configured to carry an original pattern. The CIS further includes a linear magnifying lens, provided between the light-transmitting plate and the lens, the linear magnifying lens having a characteristic of linearly magnifying an object in a single direction. The CIS involved in some embodiments of the present disclosure is capable of enhancing resolution in a single direction.