The subject innovation relates to a tape measure the length display function equipped, in the conventional tape measure 100 with a metal tape measure (101) inside the casing 10 except the front end portion 102, the appearance-disappearance possibly is wound built, said casing slides are formed at predetermined intervals on the bottom surface portion 12 which is at right angles from the side face 11 of the 10 groove (13a) and formed integrally with the guide portion 13 having an insertion aperture (13b) being spaced apart from the side surface and, a lower surface of the guide portion 13, portion 12 is provided with threaded fastening holes (13c) are formed being, is guided on the inner side of the screw coupling hole (13c), the guide slot 13, the ball lock is supported portion protruding in the 14, a locking ball and a compression spring 15 guided for elastically supporting the (14), made of a locking ball 14 and a wrench bolt (16) structure, which is installed to prevent the exit of the compression spring 15 , the slide groove (13a) and is inserted from one side of the guide aperture (13b) of the casing (10) of the guide part (13) From drawing out the marking member 20 is a bar, the marking in the direction in which a metal tape measure is pulled out from the casing side pieces, characterized in that provided with a representing the length to the object through the grid of drawn metal tape measure (101), and where to the mounted exactly on the grid of drawn metal tape measure the writing instrument by the use give to mark a location for a length portion of the object to a position toward the side of the case back when not used, with one hand even out and the length of the tape measure since the display can be useful in the field and, to therefore is completely separated from the tape measure the marking member on the need to provide the effect which can be used in parallel in the form of a conventional tape measure.