A tool device for a ground milling machine, particularly a road milling machine, a recycler, a stabilizer or a surface miner, comprising - a milling chisel having a highly wear-resistant chisel tip, particularly comprising PCD material, and a chisel shaft extending along a longitudinal axis, and - a chisel holder with a shaft receptacle, - the chisel shaft of the milling chisel has at least one tapering section narrowing in a direction away from the chisel tip, - a fastening device is provided, which is designed in such a way that it pulls the milling chisel along its longitudinal axis and in the direction away from the chisel tip into the shaft receptacle, - the shaft receptacle of the chisel holder is designed complementary to the chisel shaft of the milling chisel in such a way that the tapering section, when braced by the fastening device, at least partly bears against the chisel holder in the shaft receptacle in a frictionally locking manner, - the chisel holder comprises a base holder and a quick-change chisel holder, the base holder comprising a holder receptacle for receiving the quick-change chisel holder, and the quick-change chisel holder comprising the shaft receptacle, and - the fastening device is designed in such a way that it pulls both the milling chisel along its longitudinal axis and in the direction away from the chisel tip into the shaft receptacle and the quick-change chisel holder into the holder receptacle in the base holder, characterized in that - the milling chisel has a wear protection cap made of tungsten carbide, the chisel tip being attached to the wear protection cap by means of hard-soldering, and the wear protection cap being attached to the milling chisel by means of hard-soldering, - the milling chisel and the quick-change chisel holder each have at least one tapering section (23, 36), the tapering section of the milling chisel bearing against the quick-change chisel holder, and the tapering section of the quick-change chisel holder bearing against the base holder, the tapering sections (23, 36) of the milling chisel and the quick-change chisel holder narrowing in particular in the direction away from the chisel tip, and - the tapering sections (23, 36) of the milling chisel and the quick-change chisel holder are shaped as truncated cones and the surface lines of the truncated cones each have an angle (α, β) relative to the longitudinal axis of the milling chisel, and that the angle (α) of the tapering section of the milling chisel is larger than the angle (β) of the tapering section of quick-change chisel holder, the angle (α) of the tapering section of the milling chisel relative to the longitudinal axis being greater by at least 0.2 ° than the angle (β) of the tapering section of the quick-change chisel holder relative to the longitudinal axis. - a milling chisel having a highly wear-resistant chisel tip, particularly comprising PCD material, and a chisel shaft extending along a longitudinal axis, and - a chisel holder with a shaft receptacle, - the chisel shaft of the milling chisel has at least one tapering section narrowing in a direction away from the chisel tip, - a fastening device is provided, which is designed in such a way that it pulls the milling chisel along its longitudinal axis and in the direction away from the chisel tip into the shaft receptacle, - the shaft receptacle of the chisel holder is designed complementary to the chisel shaft of the milling chisel in such a way that the tapering section, when braced by the fastening device, at least partly bears against the chisel holder in the shaft receptacle in a frictionally locking manner, - the chisel holder comprises a base holder and a quick-change chisel holder, the base holder comprising a holder receptacle for receiving the quick-change chisel holder, and the quick-change chisel holder comprising the shaft receptacle, and - the fastening device is designed in such a way that it pulls both the milling chisel along its longitudinal axis and in the direction away from the chisel tip into the shaft receptacle and the quick-change chisel holder into the holder receptacle in the base holder, characterized in that - the milling chisel has a wear protection cap made of tungsten carbide, the chisel tip being attached to the wear protection cap by means of hard-soldering, and the wear protection cap being attached to the milling chisel by means of hard-soldering, - the milling chisel and the quick-change chisel holder each have at least one tapering section (23, 36), the tapering section of the milling chisel bearing against the quick-change chisel holder, and the tapering section of the quick-change chisel holder bearing against the base holder, the tapering sections (23, 36) of the milling chisel and the quick-change chisel holder narrowing in particular in the direction away from the chisel tip, and - the tapering sections (23, 36) of the milling chisel and the quick-change chisel holder are shaped as truncated cones and the surface lines of the truncated cones each have an angle (α, β) relative to the longitudinal axis of the milling chisel, and that the angle (α) of the tapering section of the milling chisel is larger than the angle (β) of the tapering section of quick-change chisel holder, the angle (α) of the tapering section of the milling chisel relative to the longitudinal axis being greater by at least 0.2 ° than the angle (β) of the tapering section of the quick-change chisel holder relative to the longitudinal axis.