A CMOS sensor converts optical information into an electric signal, and outputs the converted electric signal as an image signal. An imaging clock generating unit generates an imaging clock acting as a source of a drive signal that drives the CMOS sensor. A drive signal generating unit generates an imaging synchronization signal and a drive signal based on the imaging clock. A display clock generating unit generates a display clock. A display synchronization signal generating unit generates a display synchronization signal based on the display clock. A phase comparing unit compares a phase of the imaging synchronization signal with a phase of the display clock, and controls oscillation of the display clock generating unit based on a result of the comparison.
