A respirator includes a pressure relief device, a pressure measurement device, a gas delivery pipe, and a gas output control device. The gas delivery pipe fluidly circulates the pressure relief device and the pressure measurement device. The gas output control device includes a multi-way tube and a control module. The multi-way tube includes a first connection part, a second connection part and a third connection part. The third connection part is connected to the pressure measuring device and the control module The set includes a shell, a blocking element and a control unit. The shell is connected to the second connecting part and defines an exhaust flow channel. The blocking element is arranged on the shell to block or open the exhaust flow channel. The unit is arranged on the shell and is electrically connected to the blocking member for controlling its action so as to block or open the exhaust flow channel. In this way, the blocking or opening of the exhaust runner can be automatically controlled.一種呼吸器，包含一洩壓裝置、一壓力量測裝置、一氣體輸送管，及一氣體輸出控制裝置。氣體輸送管流體流通於洩壓裝置與壓力量測裝置。氣體輸出控制裝置包括一多通管及一控制模組，多通管包含一第一連接部、一第二連接部及一第三連接部，第三連接部連接於壓力量測裝置，控制模組包含一殼體、一阻斷件及一控制單元，殼體連接於第二連接部並界定一排氣流道，阻斷件設置於殼體用以阻斷或開通排氣流道，控制單元設置於殼體且電性連接於阻斷件用以控制其作動，以使其阻斷或開通排氣流道。藉此，能自動地控制排氣流道的阻斷或開通。
