Abstract: A spherical aberration correction decelerating lens corrects a spherical aberration occurring in an electron beam or an ion beam (hereinafter, referred to as “beam”) emitted from a predetermined object plane position with a certain divergence angle, and said spherical aberration correction decelerating lens comprises at least two electrodes, each of which is constituted of a surface of a solid of revolution whose central axis coincides with an optical axis and each of which receives an intentionally set voltage applied by an external power supply, wherein at least one of the electrodes includes one or more meshes (M) which has a concaved shape opposite to an object plane (P0) and which is constituted of a surface of a solid of revolution so that a central axis of the concaved shape coincides with the optical axis, and a voltage applied to each of the electrodes causes the beam to be decelerated and causes formation of a decelerating convergence field for correcting the spherical aberration occurring in the be