To obtain a novel subject compound which comprises a steroidal compound of a specific structure and is useful as a synthetic intermediate for activated type vitamin D derivative having excellent bode mass improvement, differentiation induction action and immunoregulation action with reduced side- effects.

This compound is a novel steroid represented by formula I (R1 is a protecting group for a hydroxyl group; R2 is an alkyl, an alkoxy, a protected hydroxyalkoxy; R1 and R4 are each H or methyl) and is useful as a synthetic intermediate for activated type vitamin D derivative having excellent bone mass improvement action, differentiation induction action and immunoregulation action. This compound is prepared by reaction of an epoxy alcohol of formula II (R5 is a protecting group for a hydroxyl group) with an aliphatic alcohol in the presence of an acid or alkali catalyst to form a compound of formula III (R6 is an alkyl, an alkoxy, a hydroxyalkoxy), protecting the hydroxyl group of the product followed by deprotection of the 5,7-diene and the hydroxyl protections.