PURPOSE: To improve optical performance and to prevent the damage of a flexible tube in the stage of a laser treatment by providing a pipeline connecting an image guide contained in hollow parts to a hard part provided at the top end of the flexible tube which is made solid with a synthetic resin except the hollow parts.

CONSTITUTION: An insertion part 1 is constituted of the flexible tube 5 which has the plural large and small hollow parts 2W4 extending in the axial direction and is packed with the synthetic resin except the hollow parts 2W4. The image guide fiber 6 is contained in one of the large-diameter hollow parts 3, 4 of the flexible tube 5 and a light guide fiber 7 is contained in the other. Three large and small pipelines 12, 13 having the inside diameters corresponding to the inside diameters of the hollow parts 2W4 are provided to the hard part 11 connected to the top end 9 of the flexible tube 5 in the positions corresponding to the hollow parts 2W4 so as to be penetrated in the axial direction. An optical system 15 for objective is contained in the top end of the pipeline 13 connecting to the fiber 6 and an optical system for illumination is contained in the pipeline connecting to the fiber 7.