Abstract: An object of the present invention is to provide an air bubble generation apparatus constructed in a simple structure and capable of generating fine air bubbles. Such an apparatus comprises: an apparatus body 9 having a circular column-like internal space defined by a cylindrical inner surface 3a and circular inner surfaces 5a and 7a; at least one internal cylindrical member 21 disposed within the internal space away from the cylindrical inner surface 3a; a first fluid introduction section 31 for injecting a first fluid into a tubular space between the cylindrical inner surface 3a and the internal cylindrical member 21 toward a circumferential direction; and a second fluid introduction section and a gas and liquid mixture discharge port 51, which are disposed in the circular inner surfaces 5a and 7a, respectively.