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, W denotes a hydrogen atom, a halogen atom or the like; Z denotes a 1-26C alkyl group or the like; and 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) is carried out as follows. An optically active borylvinylidene-cyclohexane compound represented by general formula (1) {wherein, W, X1 and X2 are each the same as described in general formula (3); and Ra and Rb denote each mutually independently a 1-6C alkyl group or the like or Ra and Rb are bound to denote a 2-3C alkylenedioxy or the like} or its enantiomer is reacted with a compound represented by general formula (2) Hal-Z (2) {wherein, Hal denotes a halogen atom; and Z is the same as described in general formula (3)}.