Copper fine particles were prepared by a wet chemical method using copper sulfate as a starting material, hydrazine as a reducing agent, and sodium hydroxide as a pH adjuster. It was found that there was a branch point at which the precursor changed to copper hydroxide (Cu(OH)(2)) or copper oxide (CuO), depending on the sodium hydroxide/copper sulfate molar ratio, and a range in which the particle size of the metallic copper fine particles was minimum. At higher concentrations and feeding rates of the hydrazine solution, smaller copper particles were obtained. Copper particles with a size of 0.14-2.4 mu m were obtained at a sodium hydroxide/copper sulfate molar ratio of 0.9-4.9, hydrazine concentration of 2.02-20.2 mol/L, and hydrazine feeding rate of 0.5-1.0 mL/min.