An input/output valve switching apparatus of a semiconductor manufacturing system minimizes a vibration set up while operating an input/output valve for opening and closing a wafer-transfer passage that connects chambers of the system. The switching apparatus includes a valve actuator having a close port and an open port, a first fluid line connected to the close port, a second fluid line connected to the open port, first flow regulators installed in the first and second fluid lines, respectively, to regulate the flow rate of fluid, and second fluid flow regulators installed in the first and second fluid lines to regulate the flow rate of the fluid that has passed. The second fluid flow regulators can prevent a rapid introduction of the fluid into the actuator. SEC.928