A fixing structure for fixing a reel is disclosed. The fixing structure includes a shaft having a first end having a first plurality of protrusions, and a second end having a second plurality of protrusions, wherein each of the first plurality of protrusions and one of its adjacent protrusions have a first recess therebetween, and each of the second plurality of protrusions and one of its adjacent protrusions have a second recess therebetween; and a supporting device, including a first supporting portion supporting the first end, and having a first protruding portion abutting the first recess; and a second supporting portion supporting the second end, and having a second protruding portion abutting the second recess.