A loop flow type bubble generation nozzle comprising: a loop flow type gas-liquid stirring and mixing chamber that is configured to stir and mix liquid and gas by a loop-like flow to form a fluid mixture; a liquid feed hole formed on one end of the loop flow type gas-liquid stirring and mixing chamber , the liquid feed hole being configured to feed pressurized liquid to the loop flow type gas-liquid stirring and mixing chamber ; at least one gas inflow hole into which gas can flow; a gas feed chamber formed on the other end side of the loop flow type gas-liquid stirring and mixing chamber , the gas feed chamber being configured to feed gas flowing in through the at least one gas inflow hole to the loop flow type gas-liquid stirring and mixing chamber toward one end side of the loop flow type gas-liquid stirring and mixing chamber through the entire circumference or part of the circumference while circulating the gas around a central axis of the liquid feed hole ; a jet hole formed on the other end of the loop flow type gas-liquid stirring and mixing chamber in a manner to align a central axis of the jet hole with the central axis of the liquid feed hole , the jet hole having a diameter larger than the diameter of the liquid feed hole and being configured to jet the fluid mixture from the loop flow type gas-liquid stirring and mixing chamber ; and a tapered section whose diameter continuously expands from the jet hole toward the loop flow type gas-liquid stirring and mixing chamber , characterized in that at least one cut-away part is formed on an end of the tapered section , the end facing the loop flow type gas-liquid stirring and mixing chamber . a loop flow type gas-liquid stirring and mixing chamber that is configured to stir and mix liquid and gas by a loop-like flow to form a fluid mixture; a liquid feed hole formed on one end of the loop flow type gas-liquid stirring and mixing chamber , the liquid feed hole being configured to feed pressurized liquid to the loop flow type gas-liquid stirring and mixing chamber ; at least one gas inflow hole into which gas can flow; a gas feed chamber formed on the other end side of the loop flow type gas-liquid stirring and mixing chamber , the gas feed chamber being configured to feed gas flowing in through the at least one gas inflow hole to the loop flow type gas-liquid stirring and mixing chamber toward one end side of the loop flow type gas-liquid stirring and mixing chamber through the entire circumference or part of the circumference while circulating the gas around a central axis of the liquid feed hole ; a jet hole formed on the other end of the loop flow type gas-liquid stirring and mixing chamber in a manner to align a central axis of the jet hole with the central axis of the liquid feed hole , the jet hole having a diameter larger than the diameter of the liquid feed hole and being configured to jet the fluid mixture from the loop flow type gas-liquid stirring and mixing chamber ; and a tapered section whose diameter continuously expands from the jet hole toward the loop flow type gas-liquid stirring and mixing chamber , characterized in that at least one cut-away part is formed on an end of the tapered section , the end facing the loop flow type gas-liquid stirring and mixing chamber . <EOS>