Intermediate range structures of organic-inorganic mixed superionic conductor glasses were investigated by low-angle neutron diffraction and small-angle neutron scattering (SANS) experiments. Significant small angle scatterings were observed in the glasses composed of AgI-CsI-deuterized-tetramethylammonium iodides. The fractal dimension D-f was estimated from the plot of the log I(q) vs. log q; it was 0.39 above q(c) and 2.8 below, where q(c) was a cross-over wavelength of q(c) similar to 0.02-0.05 Angstrom(-1). This result strongly supports the existence of percolation clusters in the organic-inorganic mixed superionic conductor glasses, which has been expected from ionic conductivity measurements.