in fig5 thereby shifts the backlash such that the positional relation between the document cover 6 and the hinge member 7 in an axial direction of the rotational axis therebetween is constant by the biasing member 7 c the backlash in the rotation axial direction between the document cover 6 and the hinge member 7 is shifted and the looseness is prevented especially when the apparatus is set upright the original is prevented from easily moving and the function of fixing the original is fully performed further a suction cup not shown is attached to a front end of the document cover 6 further the surface of the apparatus main body 1 opposite to the suction cup has a suction assisting smooth finish note that the sponge of the document press fixing sheet 8 has a thickness such that the sponge is slightly depressed in a state where the document cover 6 is closed and the suction cup is in intimate contact with the apparatus main body 1 in the above structure in a state where the image reading apparatus is set in level when the document cover 6 is opened the document cover 6 is press fixed to the hinge member 7 by the contact between the biasing member 7 c of the hinge member 7 and the receive member 6 c of the document cover 6 accordingly the document cover 6 does not rotate with respect to the hinge member 7 about the rotational axis.