In this paper, we consider the complex potential uω which is a solution to the equation ∇ ·((σ + iω?)∇u<SUB>ω</SUB>) = 0 in the three dimensional object Ω. If the applied angular frequency ω is sufficiently small so that the values of susceptivity ω? is relatively small compared to those of conductivity σ, it is well known that the real part ?(u<SUB>ω</SUB>) is mainly related to conductivity σ and its approximated image can be obtained from the full knowledge of the Neumann data ∂?(u<SUB>ω</SUB>)/∂non the boundary ∂Ω. Here ?(z) is the real part of the complex number z. In this paper, we consider the analyticity of the complex potential uω and show that the function Δ(??ln σ)/σ can be determined uniquely and constructablely from the full knowledge of <수식은 본문 참조>.