DIMMs to be cooled are mounted in DIMM areas of a printed circuit board of a system board. An air intake port that introduces cooling air is arranged on a side plate of the system board, whereas an air discharge port that discharges the cooling air is arranged on another side plate. The cooling air flows in a direction that is oblique with respect to the side plate. The air intake port is arranged at a position that is offset in the direction in which the cooling air is supplied. Accordingly, cooling is possible by efficiently bringing the cooling air into contact with the DIMMs.