A fine bubble generating apparatus comprising a gas swirling shearing unit, the gas swirling shearing unit including: a cylindrical member having a cylindrical inner peripheral surface; a first end wall member configured to close one end of the cylindrical member; a second end wall member configured to close the other end of the cylindrical member; a fluid swirling chamber defined by the cylindrical member, the first end wall member and the second end wall member; a fluid inlet hole extending through a wall of the cylindrical member at a position closer to the second end wall member than a center in an axial direction of the cylindrical member to introduce a gas-liquid mixed fluid into the fluid swirling chamber in a tangential direction thereof; and a fluid outlet hole extending through the second end wall member along a center axis of the inner peripheral surface of the cylindrical member; wherein the fluid inlet hole has an axis intersecting with a hypothetical axis of the fluid inlet hole and is configured to extend at an angle (θ) of from 10° to 30° to a direction, in which the fluid inlet hole would extend, if it is assumed to internally touch the inner wall surface of the fluid swirling chamber and extend tangentially about a point of internal tangency; characterized in that the inner peripheral surface of the cylindrical member is mirror-finished, and a portion of the inner peripheral surface of the cylindrical member that circumferentially corresponds to the fluid inlet hole, which opens on the inner peripheral surface, is provided with a plurality of annular grooves spaced from each other in an axial direction of the inner peripheral surface, the annular grooves having a width and a depth that are not more than 1 millimeter a cylindrical member having a cylindrical inner peripheral surface; a first end wall member configured to close one end of the cylindrical member; a second end wall member configured to close the other end of the cylindrical member; a fluid swirling chamber defined by the cylindrical member, the first end wall member and the second end wall member; a fluid inlet hole extending through a wall of the cylindrical member at a position closer to the second end wall member than a center in an axial direction of the cylindrical member to introduce a gas-liquid mixed fluid into the fluid swirling chamber in a tangential direction thereof; and a fluid outlet hole extending through the second end wall member along a center axis of the inner peripheral surface of the cylindrical member; wherein the fluid inlet hole has an axis intersecting with a hypothetical axis of the fluid inlet hole and is configured to extend at an angle (θ) of from 10° to 30° to a direction, in which the fluid inlet hole would extend, if it is assumed to internally touch the inner wall surface of the fluid swirling chamber and extend tangentially about a point of internal tangency; characterized in that the inner peripheral surface of the cylindrical member is mirror-finished, and a portion of the inner peripheral surface of the cylindrical member that circumferentially corresponds to the fluid inlet hole, which opens on the inner peripheral surface, is provided with a plurality of annular grooves spaced from each other in an axial direction of the inner peripheral surface, the annular grooves having a width and a depth that are not more than 1 millimeter