To provide a high pressure air supplier which makes it possible to easily perform an operation to an animal while considering problems and measures peculiar to the animal though in extremely simple constitution.

The high pressure air supplier comprises: a housing box 10 for housing the animal other than a human body inside a space surrounded by a case body composed of a prescribed material not to be expanded or contracted by air pressure fluctuation to at least 2 atmosphere; and a compressor 20 for supplying high pressure air whose atmosphere is higher than the atmospheric pressure into the housing box 10. The housing box 10 comprises: a door 31 for sealing the inside of the housing box 10 so as not to be opened from the inside; a control valve 35 for adjusting the atmosphere inside the housing box 10 sealed by the door 31 and supplied with the high pressure air by the compressor 20 to a prescribed atmosphere; and meters 36, 37 and 38 for indicating at least the atmosphere, oxygen concentration and a temperature inside the housing box 10.