In an electronic endoscope, an insert section has a beam splitter, a CCD, and an EMCCD at its distal end portion. When white light being normal light is applied to an internal body portion, the reflected white light is incident on the CCD through the beam splitter, and a normal image is produced. When the internal body portion is irradiated with special light being excitation light, weak autofluorescence is emitted from specific tissue of the internal body portion. The weak autofluorescence is incident on the EMCCD through the beam splitter. The EMCCD uses an avalanche multiplication effect in its electron multiplier. The EMCCD multiplies signal charge produced from the weak autofluorescence by the electron multiplier, and outputs a high level signal.