To provide a packaging container lid which has a lid member of a relatively small size, affords fine visibility in checking pouring of a content from a spout, allows one-hand operation for opening/closing the lid, ensures closing of the spout, and has a simple structure.

The packaging container 2 lid comprises a cap 3 which has the spout 12 and a connection 13 and is fitted on a container 2 to cover its opening 5, and a cover member 4 which is displaced to open and close the spout 12. The cover member 4 includes the lid member 18 which is engaged with and disengaged from the spout 12 to open/close it, a connecting member 20 which is so connected to the connection 13 of the cap 3 with the spout 12 as to be capable of rotating around a rotary shaft 14, and an elastically flexible arm member 17 which is fitted with the lid member 18 and the connecting member 20 on both ends of the arm member 17 and permits the displacement of the lid member 18 in a plane including the rotary shaft 14.