An air conditioning (A/C) apparatus, adapted to be used in a vehicle, the vehicle including a vehicle body that defines an interior space, said A/C apparatus including: a ventilation system that includes a vent pipe that is, when said A/C apparatus is mounted on the vehicle, disposed on the vehicle body, and that has an outside communicating end via which said vent pipe, when said A/C apparatus is mounted on the vehicle, communicates with the outside of the vehicle body, and an inside communicating end via which said vent pipe, when said A/C apparatus is mounted on the vehicle, communicates with the interior space; and an A/C system including an air duct that has an external inlet end via which said air duct communicates with the outside of the vehicle when said A/C apparatus is mounted on the vehicle, and a plurality of outlet ends via which said air duct communicates with the interior space of the vehicle when said A/C apparatus is mounted on the vehicle, an A/C device that is disposed in said air duct, and that is controllable to regulate temperature of air flowing through said A/C device, and a blower that is disposed in said air duct, and that is controllable to drive air to flow from said external inlet end through said A/C device to said plurality of outlet ends, said A/C apparatus being characterized in that: said ventilation system further includes a fan that is disposed in said vent pipe, and that is configurable to be activated to produce airflow from said outside communicating end to said inside communicating end when said A/C apparatus is mounted on the vehicle; a majority of said vent pipe extends along said air duct in said air duct; said outside communicating end is exposed out of said air duct; and said inside communicating end is disposed at one of said plurality of outlet ends of said air duct and communicates with said one of said plurality of outlet ends. a ventilation system that includes a vent pipe that is, when said A/C apparatus is mounted on the vehicle, disposed on the vehicle body, and that has an outside communicating end via which said vent pipe, when said A/C apparatus is mounted on the vehicle, communicates with the outside of the vehicle body, and an inside communicating end via which said vent pipe, when said A/C apparatus is mounted on the vehicle, communicates with the interior space; and an outside communicating end via which said vent pipe, when said A/C apparatus is mounted on the vehicle, communicates with the outside of the vehicle body, and an inside communicating end via which said vent pipe, when said A/C apparatus is mounted on the vehicle, communicates with the interior space; and an A/C system including an air duct that has an external inlet end via which said air duct communicates with the outside of the vehicle when said A/C apparatus is mounted on the vehicle, and a plurality of outlet ends via which said air duct communicates with the interior space of the vehicle when said A/C apparatus is mounted on the vehicle, an A/C device that is disposed in said air duct, and that is controllable to regulate temperature of air flowing through said A/C device, and a blower that is disposed in said air duct, and that is controllable to drive air to flow from said external inlet end through said A/C device to said plurality of outlet ends, an air duct that has an external inlet end via which said air duct communicates with the outside of the vehicle when said A/C apparatus is mounted on the vehicle, and a plurality of outlet ends via which said air duct communicates with the interior space of the vehicle when said A/C apparatus is mounted on the vehicle, an A/C device that is disposed in said air duct, and that is controllable to regulate temperature of air flowing through said A/C device, and a blower that is disposed in said air duct, and that is controllable to drive air to flow from said external inlet end through said A/C device to said plurality of outlet ends, said A/C apparatus being characterized in that: said ventilation system further includes a fan that is disposed in said vent pipe, and that is configurable to be activated to produce airflow from said outside communicating end to said inside communicating end when said A/C apparatus is mounted on the vehicle; a majority of said vent pipe extends along said air duct in said air duct; said outside communicating end is exposed out of said air duct; and said inside communicating end is disposed at one of said plurality of outlet ends of said air duct and communicates with said one of said plurality of outlet ends. said ventilation system further includes a fan that is disposed in said vent pipe, and that is configurable to be activated to produce airflow from said outside communicating end to said inside communicating end when said A/C apparatus is mounted on the vehicle; a majority of said vent pipe extends along said air duct in said air duct; said outside communicating end is exposed out of said air duct; and said inside communicating end is disposed at one of said plurality of outlet ends of said air duct and communicates with said one of said plurality of outlet ends.