The detail of the opening and closing control process is shown in FIG. 5. First, whether the electronic device 15 is powered on or off is determined (S110). The calculation unit 31 is connected to the electronic device 15 via wired or wireless communication, and is configured to monitor an operation state of the electronic device 15.

When the electronic device 15 is powered off (S110: NO), the artificial air aperture 30 (opening and closing section 45) remains closed (S120) and the opening and closing control process ends. When the electronic device 15 is powered on (S110: YES), temperature information is obtained from the internal environment sensor 22 and the external environment sensor 21 (S130).

Then, those temperatures are compared (S140). When the temperature outside the casing 10 (temperature detected by the external environment sensor 21) is higher than the temperature inside the casing (temperature detected by the internal environment sensor 22) (S140: YES), a command is sent to close the artificial air aperture 30 (S150). In response to the command, the artificial air aperture 30 (opening and closing section 45) is closed.

When the temperature outside the casing 10 is lower than the temperature inside the casing (S140: NO), a command is sent to open the artificial air aperture 30 (S160). In response to the command, the artificial air aperture 30 (opening and closing section 45) is open. In so doing, cool air generated by the cooling unit 25 is blown to the casing 10, and the cool air is introduced into the casing 10 via the ventilation port 40.