Provided is a length-adjustable column with a standpipe having a longitudinal axis, a length-adjustment device arranged in the standpipe with a portion displaceably-mounted along the longitudinal axis with respect to the standpipe and an anti-rotation locking device for locking the portion against a rotation around the longitudinal axis relative to the standpipe. The anti-rotation locking device includes an inner element, which is fastened to an outer surface of the portion, and an outer element, which is fastened to an inner surface of the standpipe. The inner element cooperates with positive locking with the outer element against a rotation around the longitudinal axis, and is displaceably guided along the longitudinal axis by the outer element. The inner element is connected with the portion through a substance-to-substance connecting layer.