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We explicitly calculate the S parameter in entire parameter space of the holographic walking/conformal technicolor (W/C TC), based on the deformation of the holographic QCD by varying the anomalous dimension from γ m 0 through γ m 1 continuously. The S parameter is given as a positive monotonic function of ξ which is fairly insensitive to γ m and continuously vanishes as S ∼ ξ 2 → 0 when ξ → 0, where ξ is the vacuum expectation value of the bulk scalar field at the infrared boundary of the 5th dimension z = z m and is related to the mass of (techni-) ρ meson (M ρ ) and the decay constant (f π ) as ξ ∼ f π z m ∼ f π /M ρ for ξ 1. However, although ξ is related to the techni-fermion condensate T T , we find no particular suppression of ξ and hence of S due to large γ m , based on the correct identification of the renormalization-point dependence of T T in contrast to the literature. Then we argue possible behaviors of f π /M ρ as T T → 0 near the conformal window characterized by the Banks-Zaks infrared fixed point in more explicit dynamics with γ m 1. It is a curious coincidence that the result from ladder Schwinger-Dyson and Bethe-Salpeter equations well fits in the parameter space obtained in this paper. When f π /M ρ → 0 is realized, the holography suggests a novel possibility that f π vanishes much faster than the dynamical mass m does. * ) In the case of N c = 3, this value N cr f 4N c = 12 is somewhat different from the lattice value 13) 6 < N cr f < 7, but is consistent with more recent lattice results. 14) * * ) There is another possibility for the W/C TC with much less N f based on the higher TC representation, 15) although explicit ETC model building would be somewhat involved. * * * ) This estimate 16) is based on the ladder Schwinger-Dyson (SD) equation for the gauged Nambu-Jona-Lasinio model which well simulates 10), 11) the conformal phase transition in the large N f QCD. Actually, the result is consistent with the straightforward calculation 17) of scalar bound state mass, M TD ∼ 1.5 m, through coupled use of the SD equation and (homogeneous) Bethe-Salpeter (BS) equation in the ladder approximation. Here Tr[T a T b ] = 1 2 δ ab and L(R) MN = ∂ M L(R) N − ∂ N L(R) M − i[L(R) M , L(R) N ].

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