A method for synthesizing carbon nanowires on the surface of pores or gaps present in a structure, the method comprising the steps of: (i) coating metal oxide nanoparticles on the surface of pores or gaps in a structure by infiltrating a metal oxide nanoparticle solution into the structure having the pores or gaps and drying the resulting structure by immersing the structure in the metal oxide nanoparticle solution and then creating a vacuum atmosphere, wherein the vacuum atmosphere is controlled within a range of 133.32x10 -7 to 39996.72 Pa (1x10 -7 to 300 Torr), such that the solution can be sufficiently absorbed in the pores or gaps of the structure; (ii) locating the structure coated with the metal oxide nanoparticles in a reactor and increasing the temperature in the reactor to a synthesis temperature in a vacuum atmosphere, whereby the vacuum atmosphere is controlled within a range of 133.32x10 -5 to 13332.24 Pa (1x10-5 to 100 Torr); and (iii) synthesizing carbon nanowires in the pores or gaps of the structure by supplying a carbon source into the reactor reaching the synthesis temperature and instantaneously converting the pressure condition in the reactor to a pressurization condition, wherein the reaction time during which the carbon nanowires are synthesized in the pores or gaps of the structure is controlled within a range of 1 minute to 4 hours and whereby the pressurization condition in the reactor is controlled within a range of 111457.5 to 506625 Pa (1.1 to 5 atm), and whereby the time during which the pressure condition in the reactor in the vacuum atmosphere is converted to the pressurization condition is controlled within a range of 1 to 60 seconds. (i) coating metal oxide nanoparticles on the surface of pores or gaps in a structure by infiltrating a metal oxide nanoparticle solution into the structure having the pores or gaps and drying the resulting structure by immersing the structure in the metal oxide nanoparticle solution and then creating a vacuum atmosphere, wherein the vacuum atmosphere is controlled within a range of 133.32x10 -7 to 39996.72 Pa (1x10 -7 to 300 Torr), such that the solution can be sufficiently absorbed in the pores or gaps of the structure; (ii) locating the structure coated with the metal oxide nanoparticles in a reactor and increasing the temperature in the reactor to a synthesis temperature in a vacuum atmosphere, whereby the vacuum atmosphere is controlled within a range of 133.32x10 -5 to 13332.24 Pa (1x10-5 to 100 Torr); and (iii) synthesizing carbon nanowires in the pores or gaps of the structure by supplying a carbon source into the reactor reaching the synthesis temperature and instantaneously converting the pressure condition in the reactor to a pressurization condition, wherein the reaction time during which the carbon nanowires are synthesized in the pores or gaps of the structure is controlled within a range of 1 minute to 4 hours and whereby the pressurization condition in the reactor is controlled within a range of 111457.5 to 506625 Pa (1.1 to 5 atm), and whereby the time during which the pressure condition in the reactor in the vacuum atmosphere is converted to the pressurization condition is controlled within a range of 1 to 60 seconds.