To provide a paper container that is suitable for housing an article relatively thin like a videotape cassete.

A folding paper container 10 has lid pieces 16 respectively at long sides of its rectangular opening 14 at its side end. A holding piece 20 and an insert tongue 22 are integrally formed in continuity at each of the lid pieces 16, extending over the entire length of the long side. The holding piece of the lid piece on the long side on one side is formed opposite to the insert tongue of the lid piece on the long side on the other side while the holding piece of the lid piece on the long side on the other side is formed opposite to the insert tongue of the lid piece on the long side on one side. The lid pieces 16 are bent so that the insert tongues 22 can be overlapped respectively on the opposite holding pieces 20, and with the lid pieces 16 pushed into the rectangular opening 14 at the side end, the insert tongues 22 are inserted into slits 24 and 24. With a hand detached, the lid pieces 16 tend to return to their original state because of elasticity of paper pieces, and closes the rectangular opening 14 at the side end.