The present invention relates to a device for lumbar support (2) for an office chair with a backrest consisting of a backrest frame with a membrane stretched over it, wherein the device (2) is mounted independently of the membrane in the backrest frame and is adjustable in height as well as horizontally extendable. It is characterized by the following components: Two carrier elements, identical in construction, each of which exhibits on the outside a lateral guide web (6) and a seating fixture (7) to engage a lumbar slide (8), wherein a spring element (9) is attached to the guide web (6), the spring element (9) being connected to a rigid central element, and wherein the other end of the central component lying opposite the spring element (9) is designed in the shape of a comb and exhibits individual webs, and wherein The two carrier elements, identical in construction, are turned 180° toward each other and are arranged in such a way that the webs of their two central components interlock, and A polyurethane foam element (13) applied on both sides over the central components of the two carrier elements.