To facilitate assembling operation in a pivoting structure.

A first pivoting member 60 is pivotally supported by a second pivoting member 80 by inserting a first pivot 81 to a first insert hole 60d of the first pivoting member 60 and a first through hole 80a of the second pivoting member 80. The second pivoting member 80 is pivotally supported by a pivoting member 59 by inserting a second pivot 66 to a second through hole 80b of the second pivoting member 80 and a second insert hole 59c of the pivoting member 59. A regulation member 82 includes a recess 82d to be engagingly fitted to an engagement groove 81a of the first pivot 81, a third insert hole 82e through which the second pivot 66 is inserted, and a connection portion 82b to be engaged with an engaged portion 80c of the second pivoting member 80.