PURPOSE: To prevent flicker of screen under a fluorescent light by providing a detection means detecting the strength of light incident in a photodetector or a change in the color temperature to detect whether or not a light source is a fluorescent light.

CONSTITUTION: A detection means 14 consists of an automatic balance sensor circuit 17 and BPFs 33, 34, 35. The color temperature of a light source is detected by the automatic white balance AWB sensor 13 in the circuit 17 via an optical system 15 detects the color temperature of the light source and an electric processing circuit 16 obtains output signals R/G, G/B. Then the color temperature BPFs 35 identifies whether or not the frequencies of the illuminance output change signal is 100Hz or 120Hz and the result is outputted to a control section 36. Thus, it is detected that the light source is a fluorescent light, the electronic shutter of the image pickup tube 18 is controlled to eliminate the flicker of the screen under the fluorescent light.