An endoscope characterized by a soft section thereof through which built-in components lie has a flexible tube and pluralities of metallic built-in components and nonmetallic built-in components. The method includes: if a forward error correction decoding fails, setting synchronization character of at least one of the corresponding data blocks to a first character; and performing line decoding on the data block with the set first character, and outputting decoded data. A collection canister 24 is provided between the negative pressure source 20 and the pressure distributor 40 for collecting any effluents 36 that may be drawn from the abscess 34 during application of negative pressure.