The invention provides a self-adjusting slag raking device which comprises a slag raking plate, a locking pin, a sliding seat, a support and a hinge shaft; the sliding seat comprises a check plate, a hanging rod and a two-lug plate, wherein the two-lug plate is welded on the inner side of the check plate, the hanging rod is arranged on the outer side of the check plate, and the slag raking plate with a hanging rod hole is fixed on the hanging rod through the locking pin; a single-lug plate is welded in the L-shaped support, and a bolt hole is formed on a vertical plate of the support; and the two-lug plate of the sliding seat is movably connected to the single-lug plate through the hinge shaft. The bolt used for the vertical plate of the slag raking head is connected to the front end of the telescopic arm of the slag raking machine, the slag raking plate is always propped against the tank wall to move, so that not only are the slags extremely easy to rake out, but also the collision between the slag raking machine and the hot-metal bottle can be avoided, the service life of the slag raking plate is effectively prolonged, the operation troubles of the slag raking machine and the consumption of the slag raking plate are reduced, the slag raking time can be shortened, the slag raking efficiency can be improved, the loss of molten iron can be reduced, and the temperature of putting molten iron into the furnace can be relatively increased.