PURPOSE: To allow a combustion apparatus to always become a desired burning state even if it is used in a room having different various conditions by early operating igniting time deciding means from the set time of a timer, and starting the operation of the apparatus earlier than the set time based on time data of memory means.

CONSTITUTION: Igniting time deciding means 5 reads previous time data stored in memory means 4, corrects the time data based on the difference signal of the temperature output from comparing means 8, calculates correction data to meet the time data, and finely regulates a time for starting the operation by a timer 2. Accordingly, a burner 1 is started earlier than the time set by the timer 2. Thus, it satisfactorily meets the various conditions such as the size of a room, etc., as compared with the case when the start of the operation is early started by a time decided based on a room temperature at the time of a conventional timer ignition time, and even if a combustion apparatus is installed in any room, it can satisfy a user's desire.