The device for maintaining an intervertebral space is capable of being accommodated inside the disc, in place of the core. Natural anchoring is ensured by promoting the regrowth of fibre around at least part of the device. The possibility of ejection of the residual core is limited in order to avoid a renewed hernia, and mobility of the vertebral column is ensured. To this end, a subject of the invention is a device having at least two non-expansible concentric rings which between them form a free space and which are connected to each other via two junction summits.