Abstract: A respirator is provided with a gas-metering device for respiration gases, a control unit influencing and monitoring the metering of the gas, an input unit connected to the control unit for introducing commands into the control unit, a display unit outputting parameters, a rotary knob changing preselected parameters, and with an acknowledge switch, which takes over the changed parameter as a new set value into the control unit and is actuated by the rotary knob. The display unit is designed as an interactive flat screen with a contact-sensitive surface. Data entry sectors with setting segments and output sectors for parameters to be displayed are provided within the flat screen. The input unit is designed as a keypad arranged on the side of the flat screen. At least preselected data entry sectors on the flat screen can be switched by means of the keypad.