The spherical aberration of electrostatic lenses can be corrected for the aperture angle of up to 60 degrees by introducing spherical meshes. The principle of correction is based on the capability of stigmatic imaging by a spherical refractive surface in light optics. The electrostatic potential distribution around a mesh required for the correction was studied using the analytical expression of the general solution of the Laplace equation, and the amount of aberration was determined by ray tracing. It is shown that the sign of spherical aberration at a virtual image produced by the field near the mesh can be made positive or negative, according to the position of the object and the degree of deformation of the electrostatic field from spherical symmetry when retreating from the mesh surface. It thus becomes possible to cancel the spherical aberration of a focusing field which follows the field near the mesh, and a total lens field without spherical aberration is realized. The possibility of canceling the spherical aberration is verified in a practical design example of an extraction lens for electron spectrometers, which may increase the sensitivity to much higher than that obtained with conventional lenses.