This paper considers the case where the regions of conductor‐deposited surface and the free surface are bordered by a straight line. The reflection and transmission characteristics of the surface acoustic wave are approximately analyzed, which is incident to the boundary. In the proposed analysis, the incident, reflected and transmitted fields near the straight‐line boundary are represented by the linear sums of surface waves, which are a three‐dimensional surface wave in each region with the real and complex wavenumbers, in general. The wavenumber of the surface wave on the substrate is decomposed into the longitudinal wavenumber in parallel to the straight‐line boundary and the wavenumber in the perpendicular direction. The reflection and the transmission coefficients are determined so that the discontinuity of the field near the straight‐line boundary is minimized. As a result, the analytic formula is derived for the reflection and the transmission coefficients, using only the transverse wavenumber of the surface wave. By this elaboration, a simple and approximate method of analysis is presented, which can be applied in general to the arbitrary anisotropic substrate.