A can lid shell 10 includes a panel section 11 having a circular peripheral edge, a countersink section 12 formed and recessed along the peripheral edge of the panel section 11, a chuck wall section 13 rising from an edge of the countersink section 12, and a flange section 14 protruding from an upper end of the chuck wall section 13. The countersink section 12 includes a first curved surface portion 123C that is convex toward an internal space SP1. The chuck wall section 13 includes a second curved surface portion 131 that is connected to the first curved surface portion 123C and that is concave toward the internal space SP1. Furthermore, the second curved surface portion 131 and the first curved surface portion 123C are formed to be thicker as both are directed from an edge p8 on the flange section 14 side to an edge p6 on the panel section 11 side.