To provide a heating cylinder of an indirect heating apparatus, usable for heating a food having fluidity in the production field of the food or the like, capable of preventing the food from attachment such as scorching to the inner wall of the heating cylinder by rotating a scraper in the heating cylinder, requiring no power source for rotating the scraper, arranged in the exterior of the heating cylinder, capable of being easily disassembled and cleaned, and capable of achieving miniaturization.

This heating cylinder is constituted of a heating cylinder 1 in the interior of which the object material to be heated is flowed, a screw 2 arranged in the heating cylinder 1 so as to be rotatable by the flow of the object material to be heated by centering a rotary shaft directed to the direction of the flow of the object material to be heated in the heating cylinder 1, and a scraper 3 connected to the screw 2 and having blades 4a and 4b in the inner periphery direction of the heating cylinder 1.