To reduce the diameter of a flexible pipe in an electronic endoscope provided with a three-dimensional image detector.

The electronic endoscope is provided with a housing 100 and a flexible pipe 200. An optical sending fiber 201 and an optical receiving fiber 202 are provided in the pipe 200. A light source 101 and an imaging device 104 are provide in the housing 100. A light source 101 outputs a pulse-like range finding light. The range finding light is propagated through the fiber 202 to irradiate a subject with it. Reflected light made at the subject by the range finding light is propagated through the fiber 200 to enter the imaging device 104. A photoelectric converter of the device 104 receives the reflected light to accumulate electric charges corresponding to a subject image (that is the image signal of the three-dimensional image). In the control of the accumulation operation of the device 104 by a CCD driver 107, the timing of the accumulation operation is delayed with the increase of the length of the fibers 201 and 202.