electronic device is relatively small as compared to the known techniques with remaining area of the electronic device being exposed to the atmosphere so as to cause no interference with the design of the electronic device that draw in air flow from the underside thereof and also to increase the contact area of the electronic device with the surrounding air to effect high performance of heat dissipation as shown in fig3 and 4 to practice the present invention for example a notebook computer 24 is positioned on the movable support arms 20 whereby a keypad 26 of the notebook computer is set in slight inclination with an end of the notebook computer engaging the desk top and an opposite end tightly engaging the damper pads 23 of the movable support arms 20 to securely hold the notebook computer in position thus when a user operates the keypad 26 the notebook computer 24 is set in an angular position that is comfortable for operation making it easy for the user operating the keypad 26 without feeling tired further since the inlet openings 14 and the outlet openings 15 are set in the surfaces of the top cover 11 and the lower container 10 that are perpendicular to each other the air.