The magnetic lens (magnetic field lens) uses a magnetic field rather than an equipotential plane. This work presents a modelling of the design of a focused magnetic lens. Its main purpose is to reveal the possibility of this lens to eliminate aberrations and to determine the extent of its potential to be included in the design of electron microscopes and electron beam melting systems. This work was accomplished by using COMSOL Multiphysics simulation software. The magnetic lens was tested to determine the possibility of its inclusion in electron microscopes by changing the bore radius from 1 to 4 step by step. The proposed mathematical model was proven as an excellent tool in electron optics.