Numerical solutions of electromagnetic fields are presented for the scattering by pits and guide grooves on optical disks. The boundary element method can be applied to pit scattering of various pit forms under different conditions of the incident beam. Scattering characteristics from concave or convex pits with a section of trapezoid shapes are calculated as functions of the width or the depth (height) of pits. The maximum interference effects due to disk pits are discussed, and optimum pit shapes are found. Near-field and induced currents are also studied for different polarizations.