PURPOSE: To provide a titled device which permits quicker insertion and discharge of castings and control of discharge electrodes by inserting the castings placed on a tray as they are into a water tank, supporting the discharge electrodes with a lift and moving the same to the prescribed positions with respect to the castings.

CONSTITUTION: A tray 3 carrying the work 30 is placed on a cage 19 and is inserted into a water tank 16. High voltage electricity is discharged between electrodes and the grounded work 30, and the cores of the work 30 are disintegrated by impulsive waves thereof and are settled in the bottom of the tank 16. While suitable spacings are maintained between the two electrodes 21 and the work 30 during this time, the upper part of the work 30 on the tray 3 is moved in the prescribed pattern by the combination of the movement of a travelling carriage 23 in the direction of arrow X and the movement of a transversely moving carriage 33 in the direction of arrow Y and electricity is discharged intermittently. When all of the work 30 on the tray 3 are removed of the cores, carriages 23 and 33 are returned to the home positions, and the electrodes 21 are lifted by liquid pressure actuators 22 for vertical movement.