An imaging system controller (5) outputs a control signal (VC). The control signal (VC) gives a command to output driving clocks (φVn, φHm) of an imaging element (1) in a signal transmission period, and a command to suspend output of the clocks (φVn, φHm) in an idle period subsequent to the signal transmission period. The length of the idle period is a multiple of the length of the signal transmission period by a natural number. The imaging system controller (5) periodically repeats output of the control signal (VC) giving these commands a number of times corresponding to the number of horizontal lines of the imaging element (1). In response to the commands of the control signal (VC), a timing generator (2) generates and outputs the clocks (φVn, φHm), and suspends generation and output of the same. An imaging device (10) thereby intermittently drives the imaging element (1), to generate and output a picked-up image signal (V2).