A link mechanism includes: a first link portion including a first hole; a second link portion including a second hole; a rotary shaft of a rotating body attached to the first or second link portion; a spring arranged between the first link portion and the second link portion; and a connecting pin including: a larger-diameter portion located on the first link portion at a side opposite to the second link portion and the spring and having an outer diameter larger than an inner diameter of the first hole and an inner diameter of the second hole; a medium-diameter portion having an outer diameter smaller than that of the larger-diameter portion and at least partially located within the first hole; and a smaller-diameter portion having an outer diameter smaller than that of the medium-diameter portion and at least partially located within the second hole.