An electronic endoscopic apparatus comprising: an endoscope; and an image processor, wherein the endoscope includes: an imaging unit that converts optical information into an electric signal based on a scope-side clock and a scope-side synchronization signal and output the converted electric signal as a video signal; a first multiplying/dividing unit that multiplies and/or divides a transmission clock transmitted from the image processor to generate the scope-side clock; and a scope-side synchronization signal generating unit that generates the scope-side synchronization signal, the image processor includes: an imaging-side clock generating unit that generates an imaging-side clock; a second multiplying/dividing unit that multiplies and/or divides the imaging-side clock to generate the transmission clock; a display-side clock generating unit that generates a display-side clock; an imaging-side synchronization signal generating unit that generates an imaging-side synchronization signal in the image processor; a display-side synchronization signal generating unit that generates a display-side synchronization signal in the image processor based on the display-side clock; a phase comparing unit that compares a phase of the imaging-side synchronization signal with a phase of the display-side clock and controls an oscillation of the display-side clock generating unit based on a result of the comparison; and a display timing adjusting unit that receives the video signal output from the endoscope at a timing based on the imaging-side synchronization signal and adjusts a synchronization timing of the received video signal to a synchronization timing based on the display-side synchronization signal, and a frequency of the display-side clock is M/N times a frequency of the imaging-side clock, M and N being arbitrary natural numbers. an endoscope; and an image processor, wherein an imaging unit that converts optical information into an electric signal based on a scope-side clock and a scope-side synchronization signal and output the converted electric signal as a video signal; a first multiplying/dividing unit that multiplies and/or divides a transmission clock transmitted from the image processor to generate the scope-side clock; and a scope-side synchronization signal generating unit that generates the scope-side synchronization signal, an imaging-side clock generating unit that generates an imaging-side clock; a second multiplying/dividing unit that multiplies and/or divides the imaging-side clock to generate the transmission clock; a display-side clock generating unit that generates a display-side clock; an imaging-side synchronization signal generating unit that generates an imaging-side synchronization signal in the image processor; a display-side synchronization signal generating unit that generates a display-side synchronization signal in the image processor based on the display-side clock; a phase comparing unit that compares a phase of the imaging-side synchronization signal with a phase of the display-side clock and controls an oscillation of the display-side clock generating unit based on a result of the comparison; and a display timing adjusting unit that receives the video signal output from the endoscope at a timing based on the imaging-side synchronization signal and adjusts a synchronization timing of the received video signal to a synchronization timing based on the display-side synchronization signal, and a frequency of the display-side clock is M/N times a frequency of the imaging-side clock, M and N being arbitrary natural numbers.