Provided is a new heat source device that utilizes the catalytic reaction heat as a heat source for industries. The heat source device 100 utilizing the catalytic reaction heat of silver zeolite 1 includes an accommodation container 10 for accommodating the silver zeolite 1 while ensuring air permeability, wherein the accommodation container 10 is configured to be ventilated with a mixed gas G containing hydrogen, steam, and air. The mixed gas has a hydrogen concentration of 1 to 20% by volume, a steam concentration of 1 to 95% by volume, an air concentration of 1 to 95% by volume, and a temperature of 100° C. or higher.