To manufacture three or more core sample pieces including a sample piece of a predetermined thickness from a core tube by one cutting work through a simple structure.

The core cutting device for cutting a core tube 6 filled with a core in the longitudinal direction comprises a cutting mechanism 7 of the core tube 6 and a holding mechanism 5 for holding and fixing the core tube 6 at the time of cutting the core tube 6. At least either the core tube 6 held and fixed by the holding mechanism 5 or the cutting mechanism 7 is movable in the longitudinal direction of the core tube 6, and the cutting mechanism 7 comprises two or more cutting grinding wheels 9 extending parallel to each other through a predetermined space in the longitudinal direction of the core tube 6.