To provide a heating cabinet including an airtightness keeping structure capable of keeping airtightness between a cabinet body and a heat insulation door even when the cabinet is used under a condition with extremely high-temperature and high-humidity.

One side of the heat insulation door 20 is pivotally supported to the cabinet body 10 with hinges 24, so as to be freely turned. The free end side of the heat insulation door 20 is engaged with a cabinet opening frame 15 with the use of a latch device including a latch lock 25 and a latch receiver 27. A fastening handle 18 for preventing the swelling deformation of the heat insulation door by engagement with the cabinet opening frame 15 is arranged at the free end side of the heat insulation door 20. A long-size door packing 30 to be elastically deformed is arranged in a peripheral edge part on the inner surface of the heat insulation door 20. The door packing 30 includes: a longitudinal hollow packing material 31 to be elastically deformed; and a longitudinal solid-core material 32 arranged in the hollow packing material.