To provide a post end protective device capable of performing required work without touching a cut edge and without the necessity to perform work such as chamfering the end of a post.

A post material obtained by extrusion molding is cut in prescribed length to form the posts 11, and a horizontal member 14 is extended over the upper ends of the posts 11 through height adjusting means 12 and connecting members 13. The post 11 is provided with optional mounting grooves 31 and wiring spaces S extending in a vertical direction. The height adjusting means 12 is provided with a base member 33 arranged to be placed on the upper end of the post 11, and the base member is provided in such a shape as to cover the outer edge side of the post 11 without blocking the optional mounting grooves 31 and wiring spaces S.