A position adjustment mechanism (90) includes a rack (91) fixed onto an upper surface of a second hinge member (87), a worm gear 93 that meshes with the rack (91), a handle (95) that rotates the worm gear (93), and a lever (97) that presses the second hinge member (87) against the first hinge member (85) to fix the second hinge member (87) to the first hinge member (85). The lever (97) is operated to release the pressure on the second hinge member (87) so that the handle (95) is operated, to thereby adjust a tilt of the document conveying device (27) with respect to the image reading portion (6) without using a tool and the like. After the adjustment, the lever (97) is operated to press the second hinge member (87), to thereby position the document conveying device (27) precisely at a position after the adjustment.