Information processing apparatus, particularly a plane display unit used both for a display and an inputting device is required to be small-sized when it is attached to a housing. For this purpose, a flat rectangular plane display unit (5) is attached to the housing (4) by means of fixing members (12, 13) at three positions; left and right sides and an upper central position. The left and right sides of the plane display unit (5) are fixed to a back cover (4) with screws using the fixing members (12) and the upper central position of the plane display unit (5) is clamped by the fixing member (13) to be fixed to the housing.