Abstract: Until recently no electrode system can generate both electrostatic focusing field and deflecting field in the same space without any interference. Yet this can be done if some proper continuously varying potentials that satisfy two individual field requirements are applied on the boundaries of a closed structure. For instance, a new electrostatic quadrupole of square cross-section can be used as a focusing lens and for x-y deflection simultaneously. Preliminary results of the electron-optical experiment show that the proposed structure is correct.