A fluorine-containing vitamin D2 derivative represented by the following formula
wherein R1 represents a methyl or trifluoromethyl group, and R2 represents a trifluoromethyl group when R1 is a methyl group, and a hydrogen atom or a methyl group when R1 is a trifluoromethyl group. This compound is useful for the prevention or treatment of caloium pathobolism or osteoporoeis.