To provide a process for preparing a 19-nor-vitamin D derivative.

The process for preparing the 19-nor-vitamin D derivative represented by general formula (3) (wherein, RA denotes a hydrogen atoms, a halogen atom or the like; X1 and X2 denote each mutually independently a hydrogen atom, a protecting group of a hydroxy group or a solid phase having the protecting group at the end; and Z denotes a 1-26C alkyl group or the like) is carried out as follows. An optically active vinylidene-cyclohexane compound represented by general formula (1) {wherein, RA is the same as described in general formula (3); RB denotes a halogen atom or the like; and X1 and X2 are each the same as described in general formula (3)} or an enantiomer thereof is reacted with a compound represented by general formula (2) M-Z (2) {wherein, M denotes a hydrogen atom, a BRaRb or the like; and Z is the same as described in general formula (3)}.