Abstract: In a backscattered electron detector for an electron beam apparatus which consists of scintillators, a photo-multiplier and an amplifier, a plurality of scintillators are disposed in a specimen chamber between an objective lens and a specimen and are arranged close together with their ends facing each other. The scintillators are formed with a notch at the facing ends so that a gap or opening is formed by the opposing notches to allow an electron beam to pass through the scintillators. Since each scintillator has no end portion beyond a hole, which is found in the conventional backscattered electron detector and whose electron sensing portion has low detection efficiency, backscattered electrons released from the specimen are collected by an electron sensing portion on the scintillator that is not interrupted by the hole and which thus has a high detection efficiency. This enhances the detection efficiency of the back-scattered electron detector.