An antifogging system of a vehicle includes a windshield provided between a space inside a vehicle cabin and a space outside the vehicle cabin, an antifogging coating provided on a surface of the windshield facing the vehicle cabin and configured to absorb water adhering to a surface the coating into the coating, an air conditioner configured to vaporize water absorbed in the antifogging coating, a humidity sensor configured to detect a humidity in a temperature boundary layer formed along a surface of the antifogging coating facing the vehicle cabin, and a control unit configured to operate the air conditioner when the humidity is equal to or higher than a predetermined threshold.