Mercapto group controls the adsorption and release of insulin, which is one of the proteins for enhancing the osteoblast proliferation. Silicon-ion-species were reported to stimulate the bone-forming ability of osteoblasts. The present paper describes doping with mercapto groups and silicon-ion-species in a calcium carbonate/poly (lactic acid) composite membrane, which is prepared by a sol-gel method using 3-mercaptopropyltrimethoxysilane. The membrane was amorphous and showed high flexibility. A quantitative analysis by thiol-disulfide exchange reaction using 2, 2-dipyridyl disulfide reagent showed that the amount of mercapto group existing on membrane surface was estimated to be about 5.51μmol/cm2. A trace amount of silicon-ion-species was released from the membrane after soaking in tris (hydroxymethyl) aminomethane buffer solution at 37 oC. The membrane is expected to have high bone-forming ability.