To provide a cup sleeve for controlling slip-out of a container.

A cup sleeve includes a body (111), and a damper part (200). The body (111) is formed of a heat insulating material such as paper, plastic, acryl or PET, and has a cylindrical shape capable of accommodating a container (100) including drinking cups, bottles or cans, and a cylindrical diameter at one end is larger than that at the another end. The damper part (200) is provided in an annular shape on an inner side of the body (111), and has a plurality of sheets projecting to the central axis side of the body (111). Each sheet includes at least any one of a damper sheet (201), a wrinkled sheet, a corrugated sheet and a trapezoidal sheet arranged in an annular shape at one end of the body (111).