PURPOSE: To stabilize temperature in a green house, such as a house for cultivating fruits, for a long time and to produce a necessary minimum limit heating effect by a method wherein an infinite number of through-holes are formed in an outer peripheral surface positioned approximately in the same level as that of an assembly type surrounding plate part and a charge port for live charcoal to make a fire, having an openable cover, is installed in a proper place on the outer peripheral surface thereabove to form a flue gas cylinder part.

CONSTITUTION: A given range on the lower end side forms a trumpet-form spreading- out part 31 and the spreading diameter of the release port thereof is regulated to size enough to allow it to contain in a space between ash discharge parts 12 formed on both sides of the bottom plate of a bottom support plate part 1. An infinite number of through-holes 16 are formed in an outer peripheral surface positioned approximately in the same level as that of an assembly type surrounding plate part 2 and a port 34 for charging a live charcoal to make a fire with an openable cover is formed in a proper position thereabove on the outer peripheral surface to provide a flue gas cylinder part 3. This constitution stabilizes temperature in a green house, such as a house for cultivating, fruits, for a long time by combustion characteristics specific to chaff.