Fabrication of three-dimensional metallic microstructures is an important issue for various applications in electronics and nanophotonics. Precise metallic micropatterns were fabricated by the two-photon induced photoreduction (TPPR) process. The process employs the photoreduction of silver ions in a metal ion solution composed of silver nitrate (AgNO3) and water-soluble polymer (poly(4-styrenesulfonique acid)). To improve the resolution and the uniformity of metallic micropatterns, a metal ion solution with a high concentration of silver ions was used, and the continuous forming window (CFW) of fabrication conditions was obtained by considering the mechanism of TPPR and heat effects during the process. Through this work, continuous silver lines and micropatterns with a minimum width of 560 nm were fabricated and their quality was verified.