PURPOSE: To enable proper removal of moire and to prevent lowering of resolution of an image by providing a low pass filter to reduce the occurrence of moire during connection of a fiberscope and a focus regulating means to bring a photographing optical system into a best pinpoint state by moving the optical system during connection of a hard endoscope.

CONSTITUTION: When a television camera device 12 is connected to a fiberscope 1, a photographing optical system 24 is moved in the direction of an optical axis through a focus regulating means 33 to bring it into a defocus state to an extent that observation is prevented from being difficult to make. The defocus state, coupled with a moire reducing action which a low pass filter 38 has, enables complete removal of the moire. When the television camera device 12 is connected to a hard endoscope 2 through an adaptor 13, a relay lens system serving as a transmission optical system is used for the television camera device 12 and there is no probability for moire to occur. Thereby, the position of the photographing optical system 24 can be regulated to a best pinpoint state, and since capacity of the low pass filter 38 is low, resolution is prevented from lowering.