The invention relates to an intervertebral fusion implant for fusing two adjacent vertebrae, comprising a base piece and a cover piece and also a spreading means, wherein the base piece and the cover piece are connected by a rocker which is situated therebetween and externally coupled, and the spreading means is a spreader clip on the rocker and a drive device is provided for the spreader clip. The spreader clip is used to erect the rocker such that the implant expands in terms of height. As a result of the external coupling of the rocker, a large lifting travel is available. Furthermore, the spreader clip has a blocking effect in relation to an unwanted return as a result of the frictional forces thereof.