PURPOSE: To enclose a specimen in a specimen container under vacuum, by connecting a holder to the leading end of the rotary shaft piercing through the center of the lid of a vacuum container and rotating the rotary shaft by a handle to tighten the holder under vacuum.

CONSTITUTION: Since the melt of a semiconductor such as GaAs or InP has high equilibrium vapor pressure, it is necessary to enclose a specimen container itself in a vacuum container. In order to enclose a specimen in the specimen container for measuring viscosity under vacuum, the specimen container consisting of a carbon packing 3 and a PBN crucible 4 is inserted between a carbon holder 1 having a female screw cut in the inner wall and a carbon holder 2 having a male screw cut in the outer surface. The carbon holder 1 is connected to the leading end of a rotary shaft 9 and a lid 10 is closed to evacuate the container and the rotary shaft 9 is rotated by a handle 7 to tighten the carbon holders 1, 2 under vacuum and the specimen container can be kept under vacuum by the action of the carbon packing 3.