This paper describes a synthesis method for the two‐variable variable equalizer which contains the parameter μ corresponding to the line length, and the parameter α which is independent of μ and represents the effect of the external factor. the variable transmission characteristic is represented approximately by a polynomialtype transfer function which is a mixed function of μ and a function containing α, which represents approximately the reference attenuation. This characteristic is realized by the state‐space method. By this method, an approximated transfer function is obtained taking the frequency band for the equalization into consideration, and the stability of the approximated function is secured. In addition, the construction with the minimal number of both the network providing the reference attenuation and the variable element corresponding to μ is impossible and the values of the elements are obtained directly from the coefficients of the transfer function. These are the merits of the proposed method over the traditional ones.