PURPOSE: To supply an accurate quantity of mercury, by preventing flying-away of the mercury in a supply passage and its adhesion to a wall surface, through processes of cooling and solidifying the mercury after the prescribed quantity is separated, before the mercury is supplied.

CONSTITUTION: When a cam shaft 25 is rotated by a motor, a cam roller 10 is thrusted by a cam 12 to vibrate a diaphragm 7 to pull mercury 2 into the hole 4 of a weighing plate 3. After that, a lever 5 swings in accordance with the cam diagram of the cam 11 to move the weighing plate 3 to displace its hole 4 to a position above a pipe 19. The mercury 2 is cooled and solidified by a cooling block 36. After that, a valve 21 is opened to supply the mercury into a lamp 24 through the pipe 19 by pressurized gas.