A fluid treatment unit (1) is provided. The fluid treatment unit (1) comprises a chamber, in which at least one fine grinding fluid treatment medium is accommodated. The chamber has an inlet (15) for introduction of a fluid to be treated and an outlet (16) for discharge of a treated fluid. The inlet (15) is provided at a lower portion of the chamber and the outlet (16) is provided at an upper portion of the chamber. A fluid treatment device (100) adopting the above fluid treatment unit (1) is also provided. The fluid treatment unit (1) and the fluid treatment device (100) enable the fluid treatment medium to be self-cleaned and the fluid to be treated uniformly.