To provide a functional fiber product having an improved health promotion effect.

There is provided a functional fiber product which contains a nephrite powder absorbing a terahertz wave. The nephrite preferably absorbs the terahertz wave in at least two peaks in the terahertz wave band. The nephrite preferably absorbs the terahertz wave having peaks at frequencies of about 3.34 THz and about 4.78 THz. The nephrite powder is preferably kneaded in a fiber in a spinning step. The nephrite powder is preferably fixed to a surface of a fabric.