A composite high-pressure tube, comprising an inner layer tube formed of a synthetic resin and a reinforcement layer formed by spirally winding extended polyolefin resin sheets on the outer peripheral surface of the inner layer tube, wherein the synthetic resin or heat-sealing resin forming the inner layer tube is filled into a clearance formed between the extended polyolefin resin sheets, whereby the intrusion of water from a tube cut face can be prevented; a method of manufacturing the composite high-pressure tube, comprising the steps of manufacturing the inner layer tube formed of the synthetic resin, spirally winding the extended polyolefin resin sheets on the outer peripheral surface of the inner layer tube, filling the synthetic resin forming the inner layer tube in molten state into a clearance formed between the extended polyolefin resin sheets by a shrinkage stress produced in the extended polyolefin resin sheets by heating the resin sheets in wound state, and fusing the extended polyolefin resin sheets with the inner layer tube.