To provide a combustion apparatus capable of keeping safety even if a gas leakage occurs from a gas shutoff valve to the outside of a gas supply passage.

Besides, while in use, the infrared combustion apparatus basically generates no carbon monoxide, and the probability of generating nitrogen oxides is basically zero.

Using a home-made constant-volume oxygen-bomb combustion apparatus, the change of gas pressure with combustion time of coal samples in oxygen-bomb were investigated.