A fluid fan clutch according to the present invention comprises: a fan housing provided with a housing main body having a concave fluid operating chamber formed at a center part thereof, and a housing cover, which has a concave fluid storing chamber formed at the center part thereof and is laminated to cover an opening of the fluid operating chamber, and having a fluid collecting hole and a fluid outlet respectively formed on a bottom plate and a side wall of the fluid storing chamber; a rotor rotation shaft provided so as to penetrate the bottom plate of the housing main body; a rotor fixed and coupled to the rotor rotation shaft in the fluid operating chamber; a valve ring formed in a ring-shape to be adhered to an inner wall of the fluid storing chamber and having a penetration hole formed at a point corresponding with the fluid outlet; and a check valve provided inside the fluid storing chamber as a rotatable structure to seal one of the fluid collecting hole and the penetration hole according to the rotation angle and open the other.