A cap-type synthetic resin container lid is easily removable from a container without separating to form scrap pieces, The container lid includes thin-walled inversion pieces that extend upward beyond a top panel wall from their lower ends which connect to the outer surface of a skirt wall, a restraint wall that is connected to the upper ends of the thin-walled inversion pieces and that has a specific site in the circumferential direction, and an operating section connected to the outer surface of the skirt wall via a connecting piece that extends radially out from the skirt wall at a position in alignment with the specific site. Locked projections and locking projections, on the restraint wall and the connecting piece respectively, restrict expansion of the restraint wall.