2.5-D dc resistivity modeling which allows for subsurface current and potential electrodes, numerical errors depend on the coarseness of discretization and increase with spatial wave numbers. In this regard, the exponential extrapolation of Fourier transformed potentials is useful for the evaluation of inverse Fourier transform integral in the outmost range of wavenumbers. This paper presents an accurate integral scheme in the outmost range using an exponential function of which coefficient is represented by a ratio between the modified Bessel functions of order 1 and 0. The effectiveness of this scheme has been confirmed using a homogenous half-space model and a vertical fault model.