To provide a core superior in a sliding characteristic when pulling out the core after winding a sheet-like material since a friction coefficient of a core surface is small, without damaging a sheet material, superior in an abrasion resistant characteristic, and continuously manufacturable over a long period.

This core 2 is provided for winding the sheet-like material, and surface roughness (ten point average roughness) Rz of the core surface is 0.4-5 μm, and the load length ratio tp in a cutting level of 40% is set to 20-95%. The core is desirable by covering the core surface with ceramics.

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