Superionic glasses (AgI)_0.33(Ag₂S)_0.33(AgPO₃)_0.34 and (AgI)_0.5(AgPO₃)_0.5 have high ionic conductivity at room temperature (σ ∼ 10⁻² S/cm). The inelastic neutron scattering measurements show that the superionic glass has larger intensity in low‐energy region compared with undoped insulator glass (AgPO₃). For superionic glasses we find an excess intensity above Q = 1.8 Å⁻¹ and peak profile at around 2.2 Å⁻¹ by investigating the Q‐dependent features in low‐energy region. These phenomena should be universal features of silver‐salt superionic glass. We suppose that Ag‐Ag dynamical correlation should promote the successive hopping process, and result in high ionic conductivity.