PURPOSE: To provide a method of boring an opening for mounting of floor equipment on a laying material such as a tile carpet being laid on the floor where floor equipment are attached.

CONSTITUTION: A jig member 9 is set in the opening of the top of a member 2 on floor side. The specified place of the jig member 9 is exposed by cutting off the laying material 7 positioned on the topside of the jig member 9. A guide plate 11 is set in the exposed jig member 9, and the guide plate 11 and the member 2 on floor side are squared with each other. The laying material 7 is cut by putting in a cutter knife 1 along the margin of the guide plate 11.