To prevent waterproofing butyl tape from deteriorating in a waterproofing function, even upon the occurrance of irregularities on the surface thereof by forming a projected row only on one side of the tape, a plurality of projected rows on both sides thereof, or the like regarding a waterproofing butyl tape with a plurality or projected rows continuous in a longetndinal direction.

A waterproofing butyl tape 10 has projected rows 12A to 12D on one side of a base, and projected rows 13A to 13D on the other side thereof continuously in a longitudinal direction. At the time of execution, the tape 10 is stretched and stuck to an aluminum metal fitting 200. Thereafter, a separator is peeled off and the aluminum metal fitting 200 is stuck to a building. In addition, the fitting 200 is strengthened under pressure from a roller 400. When rolling pressure is applied, the projected rows 12 and 13 can be made to properly bonded, and the internal air is forced out via a groove between the projected rows 12 and 13. Thus, the volume of the air residual in the tape 10 becomes small. According to this construction, a proper adhesion can be maintained by forming a plurality of projected rows continuous in a longitudinal direction, and a waterproofing function is not impaired.