Abstract: The present invention relates to an easy-open vessel lid which is composed of a laminate of a metal foil and a resin and has opening weakened line. A reinforcing layer of a thermoplastic resin is formed independently from the resin of the laminate at least on the outer peripheral side of a part most protruding in the opening-initiating direction of an inside introducing weakened line to cover said weakened line astride of said weakened line. By this reinforcing layer, ribbon breaking can be effectively prevented, and opening by shearing of the lid member along the weakened lines can be performed assuredly and smoothly.