  We investigate the cosmological evolution of gravitational waves in
Friedman-Robertson-Walker brane world models embedded in a five dimensional
anti de-Sitter spacetime. To predict the spectrum of stochastic gravitational
background at present generated in the inflationary phase, we numerically
calculate the evolution of gravitational waves according to the method
developed in our previous paper [K. Ichiki and K. Nakamura,
arXiv:hep-th/0310282]. The resulting logarithmic energy spectrum is
significantly altered from that of the standard four dimensional inflationary
models in the frequency range f > f_{AdS} ~ 10^{-4} Hz, which corresponds to
the curvature scale we set of anti de-Sitter spacetime, $l ~ 1$mm.
