  We discuss the sensitivity of the $e^+ e^- \rightarrow W^+ W^-$ cross section
at a future $e^+ e^-$ collider with $\sqrt{s}=500$GeV to the non-decoupling
effects of a techni-$\rho$ like vector resonance. The non-decoupling effects
are parametrized by the chiral coefficients of the electroweak chiral
perturbation theory. We define renormalization scale independent chiral
coefficients by subtracting the Standard Model loop contributions. We also
estimate the size of the decoupling effects of the techni-$\rho$ resonance by
using a phenomenological Lagrangian including the vector resonance.
