Abstract: A radiating section opening/closing apparatus in an apparatus including a housing having a radiating section while enclosing a heat generating section has at least one heat transmitting section fixed onto the heat generating section for transmitting the heat generated from the heat generating section, at least one expansion section for receiving the heat from the heat transmitting section and expanding/contracting at a specific temperature, at least one radiating section opening/closing section displaced by the expansion/contraction of the expansion section for opening/closing the radiating section, and at least one elastic member contracting/expanding while the expansion section expands/contracts for restoring the radiating section opening/closing section to an original position thereof. Thus, intrusion of foreign matters to the interior of the apparatus is blocked while externally discharging the heated air within the apparatus.