In this work, we develop a new simple synthesis method of hollow polycrystalline monophase vaterite particles without impurities such as calcite and toxic buffer (tris(hydroxylmethyl)-aminomethane: Tris). Starting materials consist of CaCl2, NaHCO3, NaCl, and a flavin mononucleotide, a vitamin B-2 derivative. The resulting vaterite particles showed a spherical shell of 2-5 mu m surrounding a 50-500 nm diameter cavity. The shells comprised 10-100 nm wide elongated fibrous crystals, which were tightly packed and radially elongated from the center of a vaterite sphere.