To provide a synthetic resin made container lid which does not cause entire separation of the container lid (2) from the container even after opening of a neck part (54) of a the container, has tamper-evident characteristics and suppresses or avoids generation of noise due to the presence of engaging means (22) arranged on the inner peripheral surface of a tamper-evident skirt part (6) in causing the body (4) of the container lid (2) separated from the neck part (54) of the container to revolve around the tamper-evident skirt part (6) before protruded pieces (28) get over an engaging jaw part (58).

Engaging means is composed of a plurality of arc-shaped engaging pieces 48a to 48f extending inward or upward in the radial direction at intervals in the circumferential direction, and the circumferential center of the protruded pieces is matched with the circumferential center of the interval between two adjacent arc-shaped engaging pieces 48a and 48f so as to avoid local deterioration of strength of the tamper-evident skirt part and avoid or reduce the interference of the protruded pieces in the engaging means.