The purpose of this study was to examine the apatite-formation ability and the viscosity of a mineral trioxide aggregate (MTA)polyvinyl alcohol (PVA) paste prepared. The MTA-PVA paste immersed in an artificial body fluid generated carbon apatite containing magnesium. The MTA-PVA paste exhibited fluidity and increased compressive strengths. It was considered possible to adjust the apparent viscosity of MTA paste by changing the concentration of the PVA solution. The MTA-PVA paste obtained using a 3-10 wt% PVA solution displayed a structural viscosity. The use of MTA may be elevated by the MTA-PVA paste with syringes in the field of endodontic treatment in order to improve MTA's operability.