A chip scattering prevention cover which is configured to be attached to a tip dresser rotary cutter including a shaft portion having a central axis aligned with a rotation axis; a disk shaped head portion formed at one end of the shaft portion and unitary with the shaft portion on a back surface side thereof to have a rotation axis aligned with the rotation axis; a curved surface formed at a center of the head portion and capable of fitting loosely an electrode tip of spot welding with a central axis of the electrode tip being aligned with the rotation axis; a cutout gap extending along the rotation axis to reach the curved surface for a continuous cutout in the shaft portion and the head portion; and a cutting part configured to be attached to an inner surface of the cutout gap, having a blade portion that extends in a direction intersecting with the rotation axis, and configured to cut by the blade portion the electrode tip loosely fitted onto the curved surface due to rotation about the rotation axis, for preventing chips created during cutting of the electrode tip by the blade portion from scattering, the chip scattering prevention cover characterized by: an annular portion configured to be detachably fitted over an outer peripheral edge of the head portion; and a plate portion extending inwardly of the annular portion from an inner circumference portion of the annular portion and configured to cover a region of the cutout gap corresponding to the head portion when the annular portion is fitted over the head portion, wherein the annular portion and the plate portion are positioned not to protrude beyond a level of a surface of the head portion when the annular portion is fitted over the head portion. to a tip dresser rotary cutter including a shaft portion having a central axis aligned with a rotation axis; a disk shaped head portion formed at one end of the shaft portion and unitary with the shaft portion on a back surface side thereof to have a rotation axis aligned with the rotation axis; a curved surface formed at a center of the head portion and capable of fitting loosely an electrode tip of spot welding with a central axis of the electrode tip being aligned with the rotation axis; a cutout gap extending along the rotation axis to reach the curved surface for a continuous cutout in the shaft portion and the head portion; and a cutting part configured to be attached to an inner surface of the cutout gap, having a blade portion that extends in a direction intersecting with the rotation axis, and configured to cut by the blade portion the electrode tip loosely fitted onto the curved surface due to rotation about the rotation axis, for preventing chips created during cutting of the electrode tip by the blade portion from scattering, the chip scattering prevention cover characterized by: an annular portion configured to be detachably fitted over an outer peripheral edge of the head portion; and a plate portion extending inwardly of the annular portion from an inner circumference portion of the annular portion and configured to cover a region of the cutout gap corresponding to the head portion when the annular portion is fitted over the head portion, wherein the annular portion and the plate portion are positioned not to protrude beyond a level of a surface of the head portion when the annular portion is fitted over the head portion.