PROBLEM TO BE SOLVED: To simply and safely expand a pericardium cavity in accordance with individual patients by suppressing excessive supply of an air into a body cavity.SOLUTION: An air supply apparatus 1 comprises: air supply means 13 and 14 for supplying a predetermined air into a body cavity of a living body and control means 21 for controlling the air supply means by switching between a first air supply mode of intermittently supplying a predetermined amount of the air at time intervals in which at least a response of the living body is detectable and a second air supply mode of supplying the air so as to keep a pressure within the body cavity to be a predetermined pressure.
