PROBLEM TO BE SOLVED: To provide a method of forming metal wiring; and metal wiring formed using the same. SOLUTION: This method of forming metal wiring includes steps of: printing wiring using an ink composition including metallic nanoparticles and a dispersant for maintaining the metallic nanoparticles in a dispersed state; primary firing of firing the wiring in a vacuum or inactive atmosphere to suppress particle growth; and second firing of firing the wiring by releasing the vacuum or inactive atmosphere to accelerate particle growth. The method of forming metal wiring induces abnormal particle growth by rapidly removing dispersant for inducing the growth of metallic nanoparticles, at a temperature at which the growth drive force of the metallic nanoparticles is high, in the process of firing the metallic nanoparticles. Thereby, the metal wiring includes a dense structure large in an average particle diameter of the particles, and excels in the electrical and mechanical characteristics. COPYRIGHT: (C)2010,JPO&INPIT