A molded body (20) containing a calcium phosphate-based material as a principal component is pulverized by a plurality of parallel extending needlelike projections (16). The molded body (20) has a plurality of pores (22) defined therein and oriented in one direction, and the needlelike projections (16) are moved, while such one direction is aligned with a direction of protrusion of the needlelike projections (16), to compressively pulverize the molded body (20). Each of the needlelike projections (16) has a diameter within the range of 1.0 to 2.0 mm and the number of those needlelike projections (16) per unitary surface area is within the range of 5 to 35 per cm 2 .
