To solve such a problem that it is impossible for a conventional technology to automatically measure the amount of roll thrust of a rolling mill stably and accurately under a light load of maintenance.

There is provided a device for measuring the amount of roll thrust of the rolling mill, which includes a pair of laser range finders 20, 20A which are arranged so that the distance between a reference point outside the housing of the rolling mill and each end face of a pair of rolls inside the housing is measurable.