PIVOT JOINT STRUCTURE

A pivot joint structure includes a first pin hole, a second pin hole, and a pin including a pin body inserted through the first pin hole and the second pin hole. The pin includes a protrusion part extending from an axis center of the pin body in a first direction, the fixation holder includes a planar part where the second pin hole is provided and a wall part rising from the planar part in the axial direction of the pin body, the wall part includes a first slit extending in a second direction and having an opening at one end, and the protrusion part is inserted into the first slit by being rotated toward the first slit about a rotation center at the axis center of the pin body.