Abstract: A charged particle energy analyzer of an electrostatic concentric spherical surface type or a coaxial cylindrical mirror type analyzes the kinetic energy of charged particles emitted or scattered from a sample by irradiating an X-ray or particles to the sample. The energy analyzer comprises the sample and an outlet aperture arranged on the symmetric central axis passing through an electrostatic concentric spherical surface body or a coaxial cylindrical mirror body, an inlet port and an outlet port each having a circular-arc-like slit which has its center on the symmetric central axis, electrodes disposed at the slit of the inlet port to deflect the track of the charged particles and change the speed of the charged particles, and a position sensitive type detector disposed at the rear of the outlet aperture to detect the charged particles.