To provide a hydrogen sulfide gas removing agent capable of being manufactured by a simple method and removing and fixing hydrogen sulfide gas in a range from a low concentration to a high concentration in a short time, and allowing confirmation of the existence of the hydrogen sulfide gas; and to provide a method of detecting hydrogen sulfide gas using the same, and a hydrogen sulfide gas removing apparatus.

Iron(III) salt and alkali are coexistently carried in a carrier with a molar ratio range of iron:alkali=1:10 to 1:20.