A holder which is disposed inside an endoscopic operation section and which fixes the flexible substrate, includes a first opening to pass the flexible substrate into the holder from the outside of the holder, a cavity portion which has a ceiling portion in the inner circumferential surface thereof and in which the flexible substrate is disposed in a bent state inside the holder, and a second opening to pass the flexible substrate to the outside of the holder from the inside of the holder. The flexible substrate is disposed separately from the ceiling portion of the cavity portion in a state where the flexible substrate protruding to the outside of the holder from the first opening and the second opening is fixed to the outer circumference of the holder.