PURPOSE:To provide the curable compsn. of 4CP and/or alpha-TCP having practicable properties meeting applications as medical materials and dental materials. CONSTITUTION:This compsn. consists of the calcium phosphate powder subjected to surface reforming by a film treatment with a high-polymer compd., the powder essentially consisting of this powder and a hardener. The resulted compsn. has excellent bioaffinity and is excellent in terms of sufficient allowance time for operation and physical properties.