To protect a sleeve and prevent water from penetrating to the base of a column by replacing a rubber winding band without removing the column.

A steel pipe column 11 is buried in a ground after waterproof treatment is applied to the base 11a of the column by the sleeve 15. The rubber winding band 17 is wrapped around the upper part of the sleeve 15 to prevent water from penetrating to the base 11a inside the band. The upper part of the rubber winding band 17 is fitted directly to the column 11 to prevent rainwater from intruding to the base through the gap between the column 11 and itself, and also presses the upper part of the sleeve 15 to prevent the sleeve 15 from being deteriorated by sunshine and weather.