disk drive 32 or the pc card slot 34 as described above because built in components are arranged without their overlapping with one another the body 3 can be made thin part of the motherboard 30 is placed under the keyboard 11 but the central processor 58 and the image processor 60 which account for a large part of the thickness of the motherboard 30 do not overlap with the keyboard 11 accordingly the body 3 is not prevented from being made thin an insulating sheet made of for example polycarbonate is laid between the part of the motherboard 30 overlapping with the keyboard 11 and the keyboard 11 in order to prevent short circuits between the case 37 of conductive magnesium and the motherboard 30 the motherboard 30 and the keyboard 11 may be arranged so that they do not overlap with each other at all because the heat generating central processor 58 and image processor 60 do not overlap with the keyboard 11 the heat of neither the central processor 58 nor the image processor 60 is transmitted to the keyboard 11 to annoy the user because the central processor 58 and the image processor 60 are disposed in the space along the back side of the case 26 and the keyboard 11 is disposed in the space along the front side of the case 26 the user can operate the keyboard 11 without touching the upper section 28 covering the central processor 58 and the image processor 60.