Micro/meso-scale (from 0.1 to 10mm) metal parts are required in electronics and medical field in recent years. Rotary forming is one of possible methods to manufacture micro axial-symmetry parts. In rotary forming, the materials are rotated and compressed in radial directions. In order to investigate the basic deformation mechanism, flat dies are used. The pins with diameters of 0.3 to 0.8mm are used to clarify the effect of size of pins on deformation behavior. Additionally, the effect of lubrication conditions on the forming process is examined. It is considered that size effects in friction behavior are recognized to be large in micro/meso-scale rotary forming.