Abstract: A length measuring apparatus for use in combination with a cutting device having a cutting blade to measure length of a workpiece cut by the cutting blade comprises a slide rail which is secured relative to the cutting device when length is measured; and a sliding unit that is slidably mounted to the slide rail, the sliding unit having a sliding body, a length measuring unit that measures distance along which the sliding body slides relative to the slide rail, and an arm member that comes in contact with the workpiece when the workpiece is placed at a cutting position; wherein the sliding unit further comprises an angle gauge member, mounted at that tip portion of the arm member which comes in contact with the workpiece, that comes in contact with the cutting blade and measures a cutting angle of the cutting blade.