The present invention provides a process for easily preparing a vinylidene fluoride homopolymer comprising an I-form crystal structure at high purity by selecting a solvent, and the process for preparing the vinylidene fluoride homopolymer comprises not less than 70% by mass of I-form crystal structure, which is obtained by dissolving a vinylidene fluoride homopolymer having a number average degree of polymerization of 3 to 20 in a solvent consisting of an organic solvent having a dipole moment of not less than 2.8 alone or comprising the organic solvent in a part, thereafter, evaporating the solvent.