PURPOSE: To enable an almost transparent flame (combustion gas) of which flame loss is hardly attained against wind and a natural red flame of which visual acknowledgement may easily be attained to be selected.

CONSTITUTION: A flame changing-over cylinder 7 is installed between anti-wind cylinders 2, 3, 6 and a mixing pipe 8. The flame changing-over cylinder can be moved to a first position where an almost transparent flame resisting against wind is made and a second position where natural red flame of which visual acknowledgement is easily attained is made. At the first position, the flame changing-over cylinder 7 opens an air suction port 8c of the mixing pipe 8 and closes a lower opening 2a of the cylinder 2. At the second position, the flame changing-over cylinder 7 closes the air suction port 8c of the mixing pipe 8 and opens the lower opening 2a of the cylinder 2. With such an arrangement as above, in the case that there is a high wind, the flame changing-over cylinder 7 is placed at the first position to get an anti-wind flame and in a room, the flame changing-over cylinder 7 is placed at the second position to enable the natural red flame of which visual acknowledgement can be easily attained to be Provided.