A novel hemostatic agent was prepared using phosphoryl oligosaccharides of calcium (POs-Ca), hydroxyapatite [Ca₁₀(PO₄)₆(OH)₂; HAp] obtained by the hydrolysis of POs-Ca (i.e., sugar-containing HAp (s-HAp), Ca/P ratio = 1.56, 60.3 mass% calcium-deficient HAp and 39.5 mass% organic materials) and thermoplastic resin (random copolymer of ethylene oxide and propylene oxide; EPO). The gel formed by mixing the EPO with water (EPO/water mass ratio: 0.20) was flash frozen at −80°C and then freeze-dried at −50°C for 15 h. The freeze-dried material was blended with POs-Ca or s-HAp. The hemostat, whose consistency had been adjusted to that of commercial hemostat by adding water, possessed the stanching times: 6.0 h (s-HAp/EPO hemostat; s-HAp/EPO = 0.20) > 5.75 h (POs-Ca/EPO hemostat; POs-Ca/EPO = 0.20) > 4.75 h (EPO hemostat). The test for the implantation of these composite hemostats into the Japanese white rabbits indicated that the bone regeneration of s-HAp/EPO composite hemostat was excellent, compared to the case of POs-Ca/EPO composite hemostat. The loading of gentamicin, a typical antibiotic agent, to the s-HAp/EPO composite hemostat showed the steady state releasing in the phosphate buffered saline.