Amorphous BaTiO3–0.27SiO2 was prepared by roller-quenching method. Crystallization was examined by DTA and X-ray diffraction. The crystals appeared are barium titanate and fresnoite; activation energies of crystals are estimated to be respectively 5 eV and 7eV. Lattice parameters of crystals were found to depend on the size of crystals. The temperature corresponding to the cubic-tetragonal phase transition of barium titanate was also found to depend on the size of barium titanate crystals.