A vehicle operating system includes an operating device disposed in a vehicle compartment and an in-vehicle device equipped to the vehicle and selecting graphical user interface displayed on a display device corresponding to selection manipulation made to the operating device. The operating device includes a base capable of being disposed by a user, a rotatable knob supported by the base, a posture detector detecting an attachment posture of the operating device, a connection unit connectable to the in-vehicle device, a manipulation signal output unit outputting a manipulation signal of the rotatable knob, and a posture signal output unit outputting an attachment posture signal. The in-vehicle device includes a display control unit controlling the display device to display the graphical user interface corresponding to the attachment posture signal, and a selection display unit controlling the display device to perform selection display of the graphic user interface corresponding to the manipulation signal.