This paper investigates the problem of diffraction of an electromagnetic wave by a semi-infinite conductor by means of the computer method based on an integral equation formulation. The cross section of the conductor can have an arbitrary shape, provided the face shined by the incident wave is a uniform plane in the region far from the edge. In that plane region, the problem is simply that of reflection from a conductor wall for which a solution is known. This known part of the solution is analytically excluded to derive an integral equation describing the edge effect over a limited region. The limited region is unknown at first and must be determined from the results of some numerical computations. As a numerical example, a thick half-plane conductor is treated in which the electric field polarization is parallel to the conductor, i.e., the case of an incident

wave.