Method of manufacturing a high pressure container having a casing reinforced with an outer composite reinforcing layer, comprising subsequent stages: A) an outer surface of the casing of the container is covered with a thin anti-adhesive layer preventing the reinforcing layer from binding to the casing; B) an impregnating mixture of a resin composition and a nanoadditive is prepared in a mixing device at a pressure lower than a normal pressure of 1013 hPa; C) the impregnating mixture is poured into a resin tray of a winding machine; D) at least one bobbin of carbon filament bundles, each carbon filament bundle containing at least 4 thousands, preferably 24 to 36 thousands of carbon filaments, are mounted on the winding machine; E) a curing agent is added to the impregnating mixture in a ratio of 29-30 wt.% of the impregnating mixture; F) the carbon filament bundles are impregnated in a resin bath with use of the resin tray so that the impregnated carbon filament bundle contains at least 65 wt.% of carbon filaments and at most 35 wt.% of composition of the impregnating mixture and the curing agent; G) the carbon filament bundles are wound on the casing by wrapping the impregnated carbon filament bundles in at least 6 different winding patterns; H) the resulting composite reinforcing layer is thermally hardened, and wherein the resin composition used for making the impregnating mixture consists of at least 75 wt.%, preferably 75-95 wt.% of bis- [4- (2,3-epoxypropoxy) phenyl] propane, and up to 25 wt.%, preferably 5-25 wt.% of 1,4-bis (2,3-epoxypropoxy) butane, the nanoadditive consists of at least 80 wt.% of graphene nanotubes, GNTs, at most 15 wt.% of iron (Fe) nanoparticles, and at most 5% of other allotropic forms of carbon such as graphene flakes or fullerenes, and moisture, wherein GNTs are single-walled graphene nanotubes, SWGNTs, and have diameter of 1-2 nm and length of at most 20 micrometers, and length-to-diameter ratio of at least 100, and wherein the impregnating mixture contains 99.9-99.99 wt.% of the resin composition, and 0.01-0.1 wt.% of the nanoadditive. A) an outer surface of the casing of the container is covered with a thin anti-adhesive layer preventing the reinforcing layer from binding to the casing; B) an impregnating mixture of a resin composition and a nanoadditive is prepared in a mixing device at a pressure lower than a normal pressure of 1013 hPa; C) the impregnating mixture is poured into a resin tray of a winding machine; D) at least one bobbin of carbon filament bundles, each carbon filament bundle containing at least 4 thousands, preferably 24 to 36 thousands of carbon filaments, are mounted on the winding machine; E) a curing agent is added to the impregnating mixture in a ratio of 29-30 wt.% of the impregnating mixture; F) the carbon filament bundles are impregnated in a resin bath with use of the resin tray so that the impregnated carbon filament bundle contains at least 65 wt.% of carbon filaments and at most 35 wt.% of composition of the impregnating mixture and the curing agent; G) the carbon filament bundles are wound on the casing by wrapping the impregnated carbon filament bundles in at least 6 different winding patterns; H) the resulting composite reinforcing layer is thermally hardened,