The production method of micro sacrificial plastic mold insert metal injection molding, namely μ-SPiMIM process has been proposed to solve specific problems involving the miniaturization of MIM. The sacrificial plastic mold (SP-mold) with fine structures was prepared by injection-molding polymethylmethacrylate (PMMA) into Ni-electroform, which is a typical LIGA (Lithographie-Galvanoformung-Abformung) process. Stainless steel 316L feedstock was injectionmolded into the SP-mold which had micro structures with multi-pillars. The green compact was demolded as one component with the SP-mold, which was decomposed along with binder constituent of feedstock in debinding process. This study focused on the effects of metal particle size and processing conditions on the shrinkage, transcription and surface roughness of sintered parts, which were evaluated by SEM (Scanning Electron Microscope) observation.