A pneumoperitoneum apparatus includes: an insufflation conduit for pneumoperitoneum； an endoscope connection tube connecting the insufflation conduit for pneumoperitoneum； an insufflation flow rate measuring section that measures an insufflation flow rate as a measured flow rate； a set flow rate setting section that sets the measured insufflation flow rate to a target set flow rate； an insufflation flow rate adjusting section； an adjustment value storing section that if the measured flow rate is equal to the target set flow rate, stores the adjustment value for the insufflation flow rate adjusting section； and a control section that if the measured flow rate varies to a value that is equal to or below a threshold value after the measured flow rate reaches the target set flow rate, performs control to set the adjustment value read from the adjustment value storing section for the insufflation flow rate adjusting section.
