A scanner is provided with a main body, a hinge, a cover member, and a plurality of sets, each set comprising a pin and a pin hole. The main body includes a transparent plate on the top surface, on which a document is placed. The hinge connects the main body and the cover member. The cover member rotates with respect to the main body between an opened state and a closed state. The cover member has a bottom surface, which makes contact with the top surface of the main body in the closed state. The pins are formed on one of the top surface of the main body and the bottom surface of the cover member, while the pin holes are formed on the other of the top surface of the main body and the bottom surface of the cover member. The plurality of sets adjusts a positional relationship between the main body and the cover member in the closed state.