To provide a lid material capable of maintaining a state that an opening part is kept exposed even when using a base material having low dead holding property.

The lid material is constituted by using a laminate structure having at least a resin film layer 2 with gas barrier properties and a sealant layer 3 for adhesion to a container, and comprises an unsealing tab 50a provided on a peripheral edge part thereof, a pair of surface half cuts 20a and 20b provided approximately in parallel from both sides thereof, a pair of locking pieces 50c and 50d provided on the side facing the unsealing tab 50a on the peripheral edge part at a spacing slightly smaller than that of the pair of surface half cuts 20a and 20b, and full cuts 10a and 10b cut in a vicinity of each front end of the locking pieces 50c and 50d in a substantially orthogonal manner to the surface half cuts 20a and 20b from the sides facing the other locking pieces.

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