A working machine according to one aspect of the present invention, includes a support member, a turn member, a pin inserted to both of the support member and the turn member to turnably support the turn member on the support member, a flange fixed to the pin, a collar inserted to an insertion hole formed in the flange, a retainer bolt inserted to the collar and attached by being screwed to the turn member and the support member, a contact portion included in the flange, and a regulator included in the support member. The regulator contacts to the contact portion with a clearance kept between the collar and an inner circumference surface of the insertion hole, thereby regulating turning of the flange around the pin.