To lessen opening and closing of a door of a melting furnace and thereby to conduct production of dissolved metal of good quality by a method wherein a prescribed number of metal thin sheets are stacked at a prescribed position and the stacked metal thin sheets are straightened in shape and also brought into close contact with each other by pressing.

A plurality of thin-sheet electrolytic copper sheets are stacked on two carry-in conveyors 1a and 1b and transferred onto carry-in conveyors 2a and 2b provided inside a loading device 3. Next, the thin-sheet electrolytic copper sheets in a plurality on the carry-in conveyors 2a and 2b are stacked one by one alternately on a loading-part conveyor 4, by prescribed numbers, by the loading device 3 and, after the sheets are stacked by the prescribed numbers, they are carried to a press device 6 by a pre-press conveyor 5. Moreover, the press device 6 presses the thin-sheet electrolytic copper sheets stacked by the prescribed numbers, synchronously with a line cycle according to a control signal from a melting furnace 12, straightens them in shape and brings them into close contact with each other. According to this constitution, opening and closing of a door of the melting furnace are lessened and thereby dissolved metal of good quality can be produced.