An internal air adjustment device (30) that includes a first composition adjustment unit (40) and a second composition adjustment unit (60). The first composition adjustment unit (40) separates supply air from external air, the supply air having a composition that differs from a composition of the external air, and supplies the supply air into a transport container (1). The second composition adjustment unit (60) separates discharge air from internal air, the discharge air having a composition that differs from a composition of the internal air, and discharges the discharge air to outside of the transport container (1). The internal air adjustment device (30) is capable of properly controlling the composition of the internal air in the transport container (1).
