The present invention relates to an apparatus and method for analyzing the energy of backscattered electrons generated from a specimen. The apparatus includes: an electron beam source (101) for generating a primary electron beam; an electron optical system (102, 105, 112) configured to direct the primary electron beam to a specimen while focusing and deflecting the primary electron beam; and an energy analyzing system configured to detect an energy spectrum of backscattered electrons emitted from the specimen. The energy analyzing system includes: a Wien filter (108) configured to disperse the backscattered electrons; a detector (107) configured to measure the energy spectrum of the backscattered electrons dispersed by the Wien filter (108); and an operation controller (150) configured to change an intensity of a quadrupole field of the Wien filter (108), while moving a detecting position of the detector (107) for the backscattered electrons in synchronization with the change in the intensity of the quadrupole field.