Disclosed is an easily openable heat seal lid for sealing a vessel proper by forming a heat-sealed portion between the lid and the vessel proper, which comprises a laminate comprising at least an inner face member composed of a thermoplastic resin and a metal foil, wherein scores defining a portion to be opened are formed on the side inner than the portion to be heat-sealed so that the scores extend to the midway of the thickness direction of the metal foil, an opening tab is formed on the portion of the lid to be opened through a bonding fulcrum portion composed of a thermoplastic resin hot adhesive so that the push-tearing top end of the opening tab is located on the scores, and the peel strength between the opening tab and the lid in said bonding portion is at least 0.4 Kg/5 mm.