PROBLEM TO BE SOLVED: To address such problems that a heat medium circulating in a double roasting drum is gradually deteriorated by long-term operations to become unusable, however, conventionally, work for discharging the heat medium and replacing it by a new heat medium is wasteful or requiring a time and a skill, and is not an effective method.SOLUTION: The roasting machine includes a double-drum type roasting drum and uses edible grains as the heat medium, where the roasting drum has a mechanism for rotating it in both forward/reverse directions. Further, the outer drum peripheral surface includes an opening, and the inner peripheral surface includes an oblique fin covering the opening and having a separately-installed tip end.
