To provide a cover cutter which can cut the cover of a covered line material crosswise easily and surely without damaging the under layer of the cover even in narrow space.

A cover cutter 11 is equipped with a holder block 20 which has a V-shaped groove 22 to receive the periphery of a covered line material 16 and a slit 24 for attachment of a cutting edge parallel with the cross section of the said V-shaped groove 22, and said cutting edge 18 which is housed and fixed in the slit of this holder block 20 in such form that the edge 18a peeps with a specified quantity of projection in the bottom space of the V-shaped groove 22. Cutting in the cover 15 such as sheath of a covered line material 16 such as an electric cable, etc., by the cutting edge 18, and rotating the cover cutter 11 will cut the cover 15 crosswise in circumferential direction.