Abstract: Provided is a double container in which an inner container and an outer container are difficult to be separated in a case where the inner container is attached to the outer container. It is a cup-shaped double container, having an inner container and an outer container in which a part of a cross section are non-circular, having a space provided between the inner container and the outer container, and having an open upper end portion, the container including: on an outer peripheral surface of a cylindrical side surface member of the inner container, a rib extending in a vertical direction and disposed in plural numbers at predetermined intervals; and a rotation regulating unit disposed on an inner peripheral surface of a cylindrical side surface member of the outer container and capable of regulating relative rotation of the inner container and the outer container by interfering with the rib.