Compressive strength of apatite type bone cement was analyzed with respect to the concentration of setting agent and types of saline solution used for storage after setting. With the increase of the concentration to 2 M, the density of paste decreased. However, the compressive strength of cement was not necessarily correlated with the density and dependent on the type of saline solution used for storage after setting. One solution led rather porous paste and the strongest specimen from the series was obtained under the maximized amount of apatite within the paste. The other saline solution induced the more dense paste after setting. In this series, the strongest specimen was obtained under the coexistence of low crystalline apatite and dicalcium phosphate dihydrate. The difference between two saline solutions was explained in terms of the solidity of skeleton formed by apatite.