Employing the maximum entropy method we extract the spectral functions from meson correlators at four lattice spacings in quenched QCD with the Wilson quark action. We confirm that the masses and decay constants, obtained from the position and the area of peaks, agree well with the results from the conventional exponential fit. For the first excited state, we obtain mπ1 = 660(590) MeV, mρ1 = 1540(570) MeV, and fρ1 = 0.085(36) in the continuum limit.