An insufflation system having a processor configured to calculate a first target gas feeding flow rate based on a difference between a body cavity internal pressure and an insufflation target pressure of a body cavity, determine whether the first target gas feeding flow rate is lower than a threshold gas feeding flow rate, and in response to determining that the first target gas feeding flow rate is lower than the threshold gas feeding flow rate, feed gas at a second target gas feeding flow rate by controlling a first valve provided at a gas feeding conduit and a second valve provided at a suction conduit, wherein the processor is configured to cause the suction conduit to suction at a first suction flow rate, and wherein the second target gas feeding flow rate is obtained by adding the first suction flow rate to the first target gas feeding flow rate.