Abstract: An electron beam length-measurement apparatus includes: an electron gun emitting the electron beam; a deflecting unit deflecting the electron beam; a detector operable to detect electrons scattered by the electron beam; a reference-substrate holding unit on which a reference substrate including a reference portion of a reference length it placed; an object holding unit on which the object can be placed; a calibration scanning controller controlling the deflecting unit; a relationship detecting unit detecting a time period of irradiation of the reference portion with the electron beam, and for detecting a relationship between a time period and length of scanning; a length-measurement scanning controller controlling the deflecting unit; and a measurement unit detecting a time period of irradiation of the predetermined portion of the object with the electron beam, and detecting a length corresponding to the detected time period of the irradiation of the object.