A pressure regulating device cooperates with a semiconductor production system to regulate a pressure in a pipe of a semiconductor production apparatus in the semiconductor production system. The pressure regulating device reduces the pressure in the pipe of the semiconductor apparatus by a suction pump to prevent from liquid leakage when the pipe is broken. In addition, the pressure regulating device can periodically record the pressure change in the pipe to facilitate an operator to judge whether the pipe is damaged and analyze the cause of decrease in production yield.