Elastic modulus, Vickers hardness, flexural strength and fracture toughness of diopside (D) glass ceramics containing 33, 38, 43 and 48wt% tricalcium phosphate (TCP) were measured. The glass ceramics were prepared by sintering and crystallization of glass powders. Precipitated crystals were diopside, β-TCP and hydroxy apatite when sintered at 1050° and 1100°C, and diopside, β-TCP and α-TCP at 1150°C. Maximum flexural strength of 67 D-33 TCP, 62 D-38 TCP, 57 D-43 TCP and 52 D-48 TCP were 223, 218, 216 and 163 MPa, respectively. Maximum Young's modulus was 122 GPa for 62 D-38 TCP, maximum Vickers hardness was 494kg/mm² for 57 D-43 TCP, and maximum fracture toughness was 2.15MPa⋅m^1/2 for 62 D-38 TCP.