PROBLEM TO BE SOLVED: To provide an evacuation apparatus usable also for introducing an inert gas, enabling quick switching between evacuation of the inside of a reaction chamber and the introduction of the inert gas in a molecular asymmetry catalyst synthesizing device etc.
SOLUTION: An evacuation line 10 is connected to a vacuum pump via a vacuum tap 13 and a solvent trap 15. An inert gas introduction line 20 is connected to an argon gas cylinder via a Young's tap 21. A decompression chamber 36 is provided at the end of the housing 35 of a tap 30 usable also for vacuum pressure. An intermediate plug 37 is drawn toward the decompression chamber 36. The lines 10 and 20 are connected respectively to the first and second ports 31 and 32 of the tap 30 and each reaction chamber of the synthesizing device is connected to a third port 33. By varying the rotational angle of the plug 37 of the tap 30, the connected state of the lines is changed.