In an insertion instrument for a three-piece intervertebral implant that includes an upper part that can be placed against a vertebra, a lower part that can be placed against the adjacent vertebra, and a pivot element that can be inserted between these two parts, the instrument having two arms, disposed side by side and supported pivotably relative to one another on one end, which at their free ends each have one retention device for the upper part and lower part, respectively, of the intervertebral implant, it is proposed that a longitudinal guide for the pivot element is disposed in one of the arms.