A lid 20 is a paper lid capable of adhering to a flange portion of a container body and includes: a tab 25; back half-cut lines 35a, 36a extending from the tab 25 outward and away from each other at an acute angle with respect to a paper grain direction K; back half-cut lines 37a, 38a extending from the outer ends of the back half-cut lines 35a, 36a, respectively, along the paper grain direction K; front half-cut lines 35b, 36b located on the outer side of the back half-cut lines 35a, 36a with a width W between the front and back half-cut lines and extending along the back half-cut lines 35a, 36a at an acute angle with respect to the paper grain direction K; and front half-cut lines 37b, 38b located on the outer side of the back half-cut lines 37a, 38a with the width W between the front and back half-cut lines and extending along the back half-cut lines 37a, 38a and the paper grain direction K.