To provide a lens fastening structure of a one-point fastening rimless frame of a near design and a simple tool which rapidly enables the exact drilling work.

The lens fastening structure of the one-point fastening rimless frame formed by providing a through-hole 1a of a deformed circle by the work of a drill 5 to drill a lens 4 with a projecting part 2a to be fitted into the through-hole 1a of the deformed circle only into an embedding portion of a screw 2 to be embedded into the through-hole of the lens 4 and attaching and inserting an elastic silicon resin, etc., into a supporting part of spectacle parts in contact with the lens and the drilling tool for the lens provided with a through-hole 3a for guide to guide the fitting-in of the drill 5, a fitting-in rod 3b to be fitted into the round through-hole 1 of the lens and a supporting rod 3d for checking the horizontal axis of the lens 4.