The invention provides an electroslag remelting device and an electroslag remelting method for refining metal scraps. The electroslag remelting device at least comprises a water-cooled crystallizer, an electrode, a bottom water tank, a power control cabinet and cables, wherein the water-cooled crystallizer is placed on the bottom water tank; a vibrating feeder for adding the metal scraps is arranged at the top of the water-cooled crystallizer; the electrode is a water-cooled electrode; the water-cooled electrode is mounted on a lifting cross arm; one end of the lifting cross arm is connected with an upright column, and can rise and fall along the upright column; the water-cooled electrode is inserted into the water-cooled crystallizer in a centering manner; the lifting cross arm and the bottom water tank are connected with the power control cabinet through the cables respectively. The electroslag remelting device is simple in structure and convenient to use, can effectively refine themetal scraps, does not bring refractory pollution, and does not cause an increase in the carbon content.