A honeycomb structural body is formed by a plurality of first wall portions, a plurality of second wall portions and a plurality of cross portions. Moreover, through holes of the honeycomb structural body are respectively defined by the first wall portion, the second wall portion and the cross portion. Further, a center portion of the first wall portion is formed by a sub material other than a main material which constitutes the honeycomb structural body. The honeycomb structural body having the structure mentioned above has excellent mechanical strength and spalling resistance.