Refrigerant relief device

A refrigerant-introducing chamber 12 in a body 10 of a refrigerant relief device and an open-to-atmosphere chamber 17 are isolated from each other by a metal thin film 13. The metal thin film 13 is tightly welded to the body 10. The metal thin film 13 receiving refrigerant pressure is positioned by a Belleville spring 19. When the refrigerant pressure reaches or exceeds a set pressure, the shape of the Belleville spring 19 is inverted to displace the metal thin film 13 toward the open-to-atmosphere chamber 17. A piercing rod 18 breaks the metal thin film 13. Refrigerant from the refrigeration cycle is released into the atmosphere.