The present invention provides a calcium cement-based bone substitute material which is safer than conventional bone substitute materials and is capable of promoting regeneration of bone tissues by means of infiltration of osteoblasts. The present invention specifically provides a paste for forming a bone substitute porous body, which contains tricalcium a-phosphate, castor oil and water. The paste for forming a bone substitute porous body is characterized in that the tricalcium a-phosphate has a particle diameter of 10-50 µm and the tricalcium a-phosphate is contained in an amount of 30-50% by weight.
