To provide an angulation ring which is a structure of an angulation portion, is formed of plastic, has high strength and a shape retaining property, and shows improved operationality in the bending operation for the structure of the angulation portion of a medical examination apparatus having an insertion part.

The angulation rings 20, 30 located in the back and front are connected to move pivotally by pivotally attaching pins 40 joining between connecting parts 22U, 32U and connecting parts 22D, 32D. Insertion openings 24 of the connecting part 22U, 22D located inside are formed into a circle, and insertion openings 34 of the connecting parts 32U, 32D located outside are formed into a quadrangle. The pivotally attaching pin 40 is constituted of a large diameter part 41 provided with a guide hole 44 for inserting an angulation control wire 8, a small diameter cylinder part 42 inserted into the insertion opening 24, and a prism part 43 inserted into the insertion opening 34. Both the angulation rings and the pivotally attaching pins are formed of a carbon fiber reinforced plastic, and the protruding part at the end of the prism part 43 of the pivotally attaching pin 40 is deformed by heat.