An imaging system includes a camera unit and a control unit. A control signal transmission circuit of the control unit is configured to set a bias potential of a signal line to one of two or more different potentials at a timing that is set on the basis of a first video synchronization signal so as to output a control signal indicating an imaging condition of an image sensor to the signal line. A signal-processing circuit of the camera unit is configured to receive the control signal and determine the imaging condition from the control signal by determining the bias potential at a timing that is set on the basis of a second video synchronization signal.