A length-measuring device includes a scale and a mounting element. The mounting element has a first fastening portion by which the mounting element is stationarily attached to the scale and a second fastening portion configured to be stationarily attached to a support. An arrangement of a plurality of flexible struts is provided between the first fastening portion and the second fastening portion which, through flexure, allows the first fastening portion to move relative to the second fastening portion perpendicularly to the longitudinal direction. The arrangement of struts is configured to compensate for a flexure-induced change in length of the struts in such a way that no movement will result from the flexure-induced change in length between the first fastening portion and the second fastening portion in the longitudinal direction.