A novel method for image reconstruction of a microwave hologram synthesized from one-dimensional data is proposed. In the data acquisition, an emitting antenna is shifted along a line. At every position of the emitting antenna, the amplitude and phase of diffraction fields are measured with a detecting antenna along a line perpendicular to the shifted direction. An equivalent two-dimensional diffraction field is synthesized from the one-dimensional data sets. The conventional reconstruction method applied to the one-dimensional configuration was the Fresnel approximation method. In this paper, an equivalent diffraction is introduced in order to obtain better images than the Fresnel approximation. An experiment made at 10 GHz shows the usefulness of the proposed method.