Micro-dies with five steps were fabricated by machining with the focused ion beam (FIB) process using two types of WC-10%Co cemented carbide with a WC grain size of 5 pro and 0.5 mum. The surface roughness of the dies was investigated by atomic force microscopy (AFM). In the coarse-grained cemented carbide, the surfaces of the WC phase were very smooth. However, those of the Co phase were rough, particularly near the interface. In the fine-grained cemented carbide, the surfaces were smoother on the whole and the irregularities of roughness were smaller compared with the coarse-grained cemented carbide, but some voids of about 0.5 pro, almost the same size as the WC grain, were observed.