We report newly synthesized high-purity samples of Y 2 C 3 with various T c 's (11.6, 13.9, and 15.2 K) and compared their superconducting properties by magnetization and specific heat measurements. From specific heat measurements, the fitting below T c to the electron specific heat of each sample has an exp (-1/ T ) dependence, as predicted by BCS theory, rather than a T n dependence, as for superconductors with an anisotropic symmetry of superconductivity. These results indicate that the symmetry of the superconductivity of Y 2 C 3 is that of an isotropic s-wave. From the fitting below T c , we estimated 2Δ/ k B T c to be 3.6, 3.9, and 4.1 for the 11, 13, and 15 K samples, respectively. We found that T c of Y 2 C 3 was correlated to the Sommerfeld coefficient, and that the high- T c material was in a stronger coupling regime than the low- T c material.