PURPOSE: To prevent the reduction of the degree of vacuum in a vapor chamber at the time of replenishing raw material metallic pellets into a chamber in an apparatus feeding the raw material metallic pellets in the chamber to a crucible below the vapor chamber through a feed pipe and a horizontal transferring tube.

CONSTITUTION: A feed pipe 5 is provided with a sluice valve 23 as well as a vacuum pipe 31 is connected to a chamber 6 via a sluice valve 25. The sluice valves 23 and 25 are closed, only the chamber 6 is separates and the control of its pressure into an atmospheric one, the replenishing of the raw material metallic pellets therein and the control of its pressure into a vacuum one are executed.