A ceramic honeycomb structural body is manufactured by molding silicon carbide raw powders into a honeycomb pillar shape and then firing it to form a sintered body. The silicon carbide raw powders are comprised of about 60 to about 80% by mass of particles of first particle group having one frequency peak in the particle size distribution and a particle size of 1.0 μm to about 100 μm, and about 20 to about 40% by mass of particles of a second particle group having a particle size of about 0.1 μm or more and less than 1.0 μm.