The freezing cycle according to the present invention is provided with a first means for safety that leaks the high pressure to the low-pressure side when the high pressure reaches a level equal to or higher than a first specific pressure, a second means for safety that releases the high pressure into the atmosphere when the high pressure reaches a level equal to or higher than a second specific pressure, a third means for safety that stops the operation of the compressor when the high pressure reaches a level equal to or lower than a third specific pressure and a fourth means for safety that releases the low-pressure into the atmosphere when the low-pressure reaches a level equal to or higher than a specific pressure. In addition, a splash-preventing film is formed over specific areas of devices constituting the freezing cycle.