Abstract: A coupling structure includes: a rod-shaped rod attached to a first end of an accessory; and a receiving portion attached to a second end of the accessory and an insertion hole portion, which receives the rod, and an accommodating portion. The receiving portion includes: a cylindrical slider into which at least a tip end portion of the rod is inserted and which is slidable and rotatable in the insertion hole and the accommodating portion; a guide groove configured to restrict the movement of the slider to switch the position of the slider to a first position or a second position; and a locking pin that inhibits the movement of the rod in the receiving portion in a pull-out direction when the slider is located at the first position and that allows the rod to move when the slider is located at the second position.