A destructive device, wherein treated material (1) including a foam body is pre-compressed in thickness direction and fed to the opposed part of a pair of compression rolls (21, 22), partition walls forming independent air bubbles in the foam body is destructed by the compression rolls (21, 22) and foam gas is arrested into a cover (3) installed on the outlet side of the compression rolls (21, 22), the foam gas is liquefied and separated by a cooling and liquefying device (6) through a cooling device (15) after pressurized, together with medium gas (41) for collection, by a pressurizing device (5), and the medium gas for collection from which the foam gas is separated is returned into the cover (3), whereby, since the foam gas is liquefied and separated in pressurized state by the cooling and liquefying device (6) by arresting the foam gas in high density inside the cover (3), the device can be remarkably downsized and simplified, and a device cost and an operation cost can also be remarkably reduced.