The invention relates to a one-piece suspension device for interposing between a mattress and a support structure. The device includes a platform defining a bearing plane for the mattress, a fastener point for fastening to the support structure, and a resilient section. The resilient section is more resilient than the platform in a direction perpendicular to the bearing plane and it is interposed between the platform and the fastener point in the direction perpendicular to the bearing plane to absorb compression forces. The one-piece suspension device is shaped such that any axis perpendicular to the bearing plane and passing through the one-piece suspension device intersects the one-piece suspension device along a single intersection segment. The resilient section has at least two elastic hinges with different flexibilities.