There is provided an insufflation system and an insufflation apparatus which can prevent a pressure inside a lumen from rapidly increasing and can achieve operability matched to a sense of an operator. When the operator operates an air/water supply button of the endoscope, the gas is insufflated into a gastrointestinal tract of a patient through an internal conduit of the endoscope (manual insufflation). Meanwhile, the insufflation apparatus is connected to an insertion assisting tool which guides the endoscope into the gastrointestinal tract. When the insufflation apparatus automatically performs insufflation, the gas is intermittently insufflated into the gastrointestinal tract of the patient so as to maintain the pressure inside the gastrointestinal tract at the set pressure (automatic insufflation). The average flow rate of the gas in the automatic insufflation is set to be less than or equal to the insufflation flow rate in the manual insufflation.