This measuring device is provided with: measurement markers (2) that are provided on the outer circumferential surface of a drum (3) having a strip-like member (10) disposed on the outer circumferential surface; at least one measurement sensor (4) that acquires positional information of at least some of the measurement markers (2); and a calculating means, which calculates the positions of the measurement markers (2) on the basis of measurement information of the measurement markers (2), said measurement information having been acquired by means of the measurement sensor (4), and which calculates displacement between previously measured actual positions of the measurement markers (2) and the calculated positions of the measurement markers (2).