PURPOSE: To make it easy to adjust the length of exposure of a combustion wick by forming suitably the shape of a groove provided on a rotating cylinder which is rotated by a drive motor and making the connection and releasing between the rotating cylinder and a mechanism to raise or lower the combustion wick simple.

CONSTITUTION: A connecting rod 40 has its center journaled and is provided at its one end with an engagement pin 41 which projects and is slidably fitted into the groove 38 of a rotating cylinder 39, and its other end is interlinked with an operation lever 13 which is for raising and lowering the combustion wick through a spring 42. The engagement pin 41 at the highest end of the groove 38 ignites the combustion wick 4 by an ignition mechanism 26 and at the terminal end of a parallel section 45 stops the rotation of the rotating cylinder 39 to continue the state of combustion. Further, at the position of starting a wide groove of a manual operation section 47 is provided at the upper end of the groove 38 so that the engagement pin 41 can be moved up and down freely, and the groove at the lower end of the parallel section 45 is cut off from the terminal end to the position of starting to provide an adjustment section 48 so as to allow the engagement pin 41 to go up and down freely. When the combustion is stable, the length of exposure of the combustion wick 4 is adjusted freely by an operation lever 13 to achieve complete combustion.