Abstract: A positioning scale device includes a main scale body (1), a stationary positioning portion (2), at least a moving positioning portion (3), and at least a direction indicating portion (4). The main scale body (1) has at least a guiding slot (11); the stationary positioning portion (2) being positioned on the main scale body (1) is adjacent to an end of the guiding slot (11); the moving positioning portion (3) being positioned in the guiding slot (11) is capable of fixing at a location of the guiding slot (11); while the direction indicating portion (4) being positioned on the main scale body (1) forms a predetermined angle with respect to the extended direction of the guiding slot (11). By the use of the direction indicating portions (4), one is capable of assuring relationship between the “object to be measured” and the horizontal direction. Therefore, the positioning scale device of the invention is capable of achieving the efficacy of duplicating the same status as that of the “object to be measured”.