A ventilation structure includes a metal housing and a ventilation member. The metal housing is a housing that requires ventilation, and has a ventilation hole and a hole-surrounding portion. The ventilation hole is covered by the ventilation member. The hole-surrounding portion defining the periphery of the ventilation hole has been subjected to an alumite treatment, a treatment for forming a chemical conversion coating formed by a trivalent chromium compound, a chromium-plating-on-aluminum treatment, or an oil-repellent treatment.