An imaging system having an imaging device for producing images of objects and picture signals and an imaging controller connected to the imaging device through a transmission line. The imaging device includes a vertical synchronizing signal-producing circuit to produce an internal vertical synchronizing signal for the production of images of objects. The imaging controller includes a delay-measuring circuit and a vertical-synchronization phase-advancing circuit. In the system, the imaging controller transmits a test signal to the imaging device and receives the test signal returned from the imaging device. The delay-measuring circuit measures a delay of a phase of the returned test signal relative to a phase of the transmitted test signal. The vertical-synchronization phase-advancing circuit then advances a phase of an external vertical synchronizing signal by the delay and transmits the external vertical synchronizing signal to the imaging device. The vertical synchronizing signal-producing circuit at the imaging device is reset by the phase advanced external vertical synchronizing signal transmitted from the vertical-synchronization phase-advancing circuit.