Cellular activities of human mesenchymal stem cells (MSCs) and osteoblasts (HOBs) on a silicon-releasable scaffold, which is siloxane-doped poly(lactic acid) / vaterite composite coated with hydroxycarbonate apatite (SPV-H), were estimated using two types of media, with or without organic factors, dexamethasone (Dex) and β-glycerophosphate (β-GP). The culture tests using MSCs shows that the level of alkaline phosphatase (ALP) activity in the cells cultured on SPV-H increased for 21-day culturing in medium without Dex and β-GP. The proliferation of MSCs on SPV-H was significantly higher than that on a poly(lactic acid) / vaterite composite coated with hydroxyapatite (PV-H) at all time points. In the case of supplementing Dex and β-GP to the medium, the level of ALP activity in MSCs cultured on SPV-H was higher in comparison with that on PV-H at all time points. Scanning electron microscopy showed that there were some agglomerates in HOBs cultured on the SPV-H surface after 21-day culturing in the medium without the factors, while there are no agglomerates on PV-H. The agglomerates were regarded from laser Raman spectroscopy as bone nodules. This result implies stimulation to HOBs by silicon species in SPV-H. SPV-H is expected to be useful as the scaffold for bone tissue engineering.