PURPOSE: To improve the working efficiency, to reduce the manufacturing cost, and to enable the casting of the rare earth magnetic alloy etc., excellent in equality and easy to be pulverized by providing a truck room in which the atmospere such as vacuum and, inert gas is adjustable, and a pair of molds and truck for spare.

CONSTITUTION: A die 43 where the casting work is completed is stored in a truck room 50 which is preliminarily kept in the atmosphere such as vacuum together with a truck 45, and a spare die and a spare truck are alternately stored in a vacuum tank 31. Immediately after an intermediate door is closed, the following melting work is started, and the die 43 loaded with the ingot during the melting work is moved outside of the truck room 50 together with the truck 45, and the works such as taking-out of the ingot, cleaning of the die, movement to the truck room, and adjustment of the atmosphere can be achieved inn parallel to the following melting work in an extensive space outside the vacuum tank. Thus, the rapid cooling can be realized to improve the quality and crushability of the rare earth magnetic alloy and the hydrogen storage alloy.