of the enclosure 12 through the air intake opening 29 a back panel 31 is placed in the inner space of the enclosure 12 the back panel 31 stands upright in the vertical direction the system board units 14 and the input output units 13 are coupled to the front surface of the back panel 31 the electronic component units 32 and the input output units 13 is coupled to the back surface of the back panel 31 the individual electronic component unit 32 includes an interface unit controlling the interface of the server computer 11 and a controller unit controlling the processing of the server computer 11 for example the electronic component unit 32 includes a printed wiring board extending in the horizontal direction here a predetermined interval may be defined between the electronic component units 32 and the inward surface of the side panel 12 b the fan units 15 serve to generate airflow running in the vertical direction from the air intake opening 29 the pci boards of the input output units 13 and the system boards of the system board units 14 stand upright in the vertical direction the airflow thus runs in the vertical direction through the input output units 13 and the system board units 14 the airflow absorbs heat from the pci boards and the electronic circuit elements in the system board units 14 the pci boards and the electronic circuit elements are thus prevented from a rise in temperature the airflow then enters gaps between the power source unit sets 16 fig5 is a front view of the server computer 11 the arrows stand for airflow in fig5 referring also to fig5 the airflow runs in the vertical direction between.