Producing micro size parts by metal injection molding (μ-MIM) needs more sophisticated technique than conventional MIM. Especially, to fill the micro groove cavities which size are smaller than 10 μm with feedstock by μ-MIM technique, much smaller particle size of powders than that of conventional MIM are required. Also, various properties such as powder loading and viscosity of feedstock, debinding behavior of compacts, relative density and mechanical properties of sintered compacts would be changed by using fine powders. In this study, the effects of particle size of powders on the properties of stainless steel (SUS316L) compacts were investigated for μ-MIM processing. The sintered compacts using fine powder which mean particle size is 3 μm showed high density and tensile strength.