Abstract: A combustion safety arrangement in which a switch is connected in an electrical power circuit for an electromagnetic valve in a fuel passage. A combustion detecting element responds to a change of a flame caused by incomplete combustion or the like, and generates a signal or change in an electrical characteristic. The switch and the combustion detecting element are interconnected through a control circuit which has a level detector for detecting a predetermined level of the change in electrical characteristics. The arrangement is such that the switch may be opened by the predetermined level of the change in electrical characteristics. The control circuit has a time limit operation circuit so that only when the generation of the change in electrical characteristic is continued for a delayed time set by that time limit operation circuit, the switch may be opened.