In this study, 316L stainless steel powder was used to produce a porous body that could be used in a specific environment. In contrast to the existing method of producing filters using only spherical powders, we attempted to produce filters using plate- and needle-like powders and evaluated their performance. In the powder preparation step, the shape change of the powder was analyzed by changing the size of the stainless-steel balls used for ball milling. Then, the variations in properties of the sintered porous body caused by the ball size were investigated. As the average ball size decreased, the average particle size of the powder decreased. Moreover, the surface area and pore size of the porous body decreased. Additionally, when balls of different sizes were mixed, the porous body showed a mixture of coarse and fine pores.