An onboard air conditioning device wherein the heating capability of air conditioning is improved, and gas is prevented from flowing into the vehicle interior even in the unlikely event that gas is produced by a battery. In this device, one end of an air flow channel is connected to an air conditioning unit for blowing temperature-regulated air into a vehicle interior, and the other end opens into the vehicle interior. The air flow channel draws air into the vehicle interior from the opening, the intake air is passed through a battery and heated by heat exchange, and the air is then sent to the air conditioning unit. The air conditioning unit sends the air from the air flow channel to a sensible heat exchanger, and after this air undergoes heat exchange with air taken in from another channel, the air is exhausted out of the vehicle interior.