PURPOSE: To obtain a pin-shaped extremely fine wire which has a uniform density, and a super-abrastion resistance and a corrosion resistance by bringing a drawn extremely fine wire to a primary HIP processing by using a gaseous argon as a pres sure medium, annealing, hardening and cutting it, and thereafter, bringing it to a secondary HIP treatment at a low temperature.

CONSTITUTION: In a wire drawing process 1, a rod-shaped member 2 is made to pass through a die 3 having a small diameter successively and drawn, and it is drawn to an extremely fine wire 2A. While this wire drawing is executed, a spheroidizing annealing 4 is executed. The wire 2A is made to pass through the HIP processing 5. The gaseous argon used as a pressure medium, the inside of an HIP body 6 is brought to a pressure processing for a prescribed time by 1,000W1,200 atmospheric pressure, and the density of the whole is densified. An extremely fine wire 2B which was brought to the HIP processing is brought to the processing of an object wire diameter wire drawing 9 and hardening 10, and thereafter, made to pass through a cutting device 11, and a pin-shaped extremely fine wire 2C is formed. Subsequently, it is fed to the second HIP processing 12, brought to a pressure processing for a prescribed time by ≥1,000 atmospheric pressure and at 500W600°C, and a nitriding layer is generated. By this treatment, the pin-shaped extremely fine wire having a uniform organization having 100% density is obtained.