A contact-type image sensor is designed to prevent, in an effective manner, dust from entering into a space between a rod lens array and a light receiving sensor. A rod lens array includes a large number of rod lenses between two flat substrates and between spacers located at left and right ends; one row of the rod lenses is arranged in such a way that central axes of the rod lenses become parallel to each other. At an emission side of a rod lens in an axis line direction, each substrate includes an extension portion, whose length is determined based on an operating distance of the rod lens. A lower end of the extension portion of each substrate is in contact with an upper surface of a sensor substrate. In this manner, the rod lens array is positioned with high accuracy with respect to the light receiving sensor.