The effect of characteristics of powder on mechanical properties of sintered SUS304L compacts made by injection molding was investigated. The specimens were made by injecting the mixture of water atomized or gas atomized powder and a polyamide binder into a metallic mold. The compacts were debound in air and sintered in vacuum at the various temperatures between 1573K and 1673K for 7.2ks. The relative densities of the sintered gas atomized powder compacts were higher than those of the sintered water atomized powder compacts. Some amount of oxide was found to exist in the microstructure of sintered water atomized powder compacts. The tensile strength and elongation of sintered gas atomized powder compacts were higher than those of sintered water atomized powder compacts mainly because of their relatively higher densities. The highest density of all was 70%. On the other hand, the proof stress and hardness of the sintered water atomized powder compacts were higher because of the existence of oxides.