A vacuum exhaust method is for decreasing a pressure in a processing chamber in which a mounting table configured to mount thereon a substrate is provided by using a gas exhaust unit. The vacuum exhaust method includes mounting a non-evaporated getter (NEG) on the mounting table, and adsorbing an active gas in the processing chamber on the NEG mounted on the mounting table. In the adsorbing the active gas, the NEG is maintained at a predetermined temperature.