To provide a fire safety apparatus for low-pressure chamber for securing the safety of a person entering a low-pressure chamber when causing a fire inside/outside the low-pressure chamber.

The low-pressure chamber constituted by of a low-pressure chamber housing, a pressure control mechanism for controlling the pressure inside the low-pressure chamber housing, and a vacuum pump for sucking air inside the low-pressure chamber housing and reducing the pressure. This low-pressure chamber fire safety apparatus is provided with a fire alarm inside the low-pressure chamber housing of the low-pressure chamber, when occurring a fire, actuates sprinklers to extinguish the fire, is further provided with a fire alarm outside the low-pressure chamber, when occurring a fire in the surroundings of the low-pressure chamber, actuates the sprinklers to cool the low-pressure chamber and, when the fire alarms provided inside/outside the low-pressure chamber are actuated, automatically actuates a voice box or a warning light to notify the occurrence of the fire to the inside/outside of the low-pressure chamber.