A method of recycling a composite container for a high-pressure gas includes the following steps: separating the composite container for a high-pressure gas and a facility connected to the composite container, wherein the composite container includes an inner container and an outer container; cutting the separated composite container; separating the inner container and the outer container from the cut composite container; performing heat fusing on the separated inner container and recycling the fused inner container; retaining the separated outer container on a recovering rod of a carbon fiber recovering device, and separating and recovering fibers in the separated outer container through a thermal decomposition method, wherein the carbon fiber recovering device includes the recovering rod retaining the separated outer container and a pair of support members for supporting the recovering rod; and recycling the recovered carbon fibers.