To provide a core material easily handlable during manufacturing of a sheet-type object, with volume easily and substantially reduced after finishing the role of the core material, and a rolled-up product using the core material.

For the core material for the rolled-up product, a plastic tube filled with air is used as a core material, instead of a cardboard tube. A check valve 2 is inserted from the end part of a plastic tube main body 1 to its inside and is heat-sealed.