To make it possible to surely move a cap for adjusting heating power to a position where the specified heating power is obtainable by making this cap slidable to a wide angle range and to enable a user to easily adjust the heating power even when a windproof cooking stove is used as a base for placing a pan, etc.

This device has a container 3 which houses a fuel can 2 and a cover 6 which is a cover to be placed at the top end of the container and has an aperture 4. The top surface of the cover is provided with the cap 15 which is fixed with a ring 11 by means of three sets of fixing members 12 and 14 and is capable of varying the size of the aperture 4 between the ring and the cover. A stopper pin 16 is erected at the cap and the cap 15 is made slidable within a range where the cap is regulated by the fixing members 12 and 14 and the stopper ring 16 is regulated by the inner periphery of the ring. The cap 15 is made slidable in the wide angle range so that the size of the aperture 4 may be changed by sliding the cap 15 even if there is no sufficient space between the base placed around the container 3 and the container.