A method of manufacturing a medical elongated body including an inner layer, an outer layer covering the outside of the inner layer, and a reinforcement body provided between the inner layer and the outer layer. The method includes an inner layer forming step of forming the inner layer, a reinforcement body forming step of forming the reinforcement body on an outer peripheral surface of the inner layer after the inner layer forming step, a cooling step of cooling at least a predetermined spot of the inner layer after the reinforcement body forming step, and an annealing step of annealing the reinforcement body which overlaps the predetermined spot of the inner layer cooled by the cooling step.

A metal-resin composite, a surface treatment method, and a substrate of a printed circuit board (PCB) for high-frequency and high-speed signal transmission comprise a surface-treated metal, and the surface-treated metal includes a nano-scale pore array that is used for filling of a resin and vertically extends from a surface to an interior of a metal, where nano-scale pillars are provided to extend from bottoms to openings of nano-scale pores of the nano-scale pore array. The pillar-in-pore structure makes a resin entering a nano-scale pore have an ultra-high anchoring effect on a resin body outside the nano-scale pore. Therefore, on the premise of not using an additive such as a T liquid or a coupling agent, the present disclosure greatly improves a tensile bonding strength at an interface between a resin body and a metal substrate, and also eliminates a decline in an interfacial bonding strength of a composite.