Pore structure in a ceramic green body was directly observed with a novel characterization tool to examine the detrimental effect of a binder on the microstructure of ceramics for powder compaction processing. The binder segregated on the surface of granules and formed a low-density region at the boundaries of granules in the compact after binder removal. A network of pores with round shapes was produced in the sintering process from the low-density region. This paper also explains a new characterization technique, confocal laser scanning fluorescent microscopy.