To provide a fitting device of a reel bobbin with a raw material yarn wound therearound to a yarn working device such as a yarn twisting machine which is compact in size, low in the height of the device, and simple in structure.

A fitting device is provided with a truck 1 provided with an elevating/lowering working platform 4 and a cargo handling device 33 installed on the truck or the working platform, the cargo handling device 33 is provided with a horizontal expandable arm 19 which is mounted on a pole 8 in an elevating/lowering and turnable manner, a gripper 22 provided on a tip of the horizontal expandable arm, and an elevating/lowering device 14 to elevate/lower the horizontal expandable arm 19 along the pole 8. An oscillating device 23 to change the direction of the gripper 22 downward and transverse in the horizontal direction is also provided. When a reel bobbin is held by the gripper 22 provided on the tip of the horizontal expandable arm 19, the reel bobbin can be held approximately at the height of the arm. Because the arm 19 is elevated approximately to an upper end of the pole 8, the reel bobbin can be fitted even when the creel of the yarn working device is at the height immediately below the ceiling.