The present invention relates to a nanobubble-and-hydroxyl-radical generator and, more particularly, to a system for processing polluted water without chemicals comprising: an air supply unit; an inlet pipe, connected to the air supply unit, for introducing a fluid; the nanobubble-and-hydroxyl-radical generator, comprising a pump connected to the inlet pipe, a drive motor connected to the pump, rotary blades connected to the drive shaft of the drive motor, and fixed blades connected to the inner wall of the pump and disposed between the rotary blades; and a discharge pipe, connected to the nanobubble-and-hydroxyl-radical generator, for discharging a nanobubble-generated fluid, wherein the circumferential surface of the rotary blades or the fixed blades, or both, is formed to be inclined inone direction. As such, the present invention provides a nanobubble-and-hydroxyl-radical generator capable of further enhancing a dissolution rate in such a manner that the circumferential surface ofeach blade is inclined to induce a disturbance phenomenon of air and a fluid, thereby accelerating micronization and mixing of air and a fluid.