To prevent rod winding from being formed at the traverse position of a bobbin at the start of winding by setting the thread releasing positions of thread hook sections at the positions off the center position of a traverse range.

Thread guard sections are formed on an inside flange 5 and an outside flange 6 across a peripheral groove 7 on at least one of a pair of bobbin holders 2. When a thread guard arm 31 is located at a thread guard position, an inside thread hook section 32 is located inside of the flanges 5, 6, and it is protruded so that its rotating orbit (a) crosses the flanges 5, 6. An outside thread hook section 33 is located outside of the flanges 5, 6, and it is protruded so that its rotating orbit (b) does not cross the flanges 5, 6. The rotating orbits (a), (b) are made about a half of the length of a bobbin B so that the thread guard arm 31 is compactly stored in a winding device. The height (h) of the hook section 50 of the inside thread hook section 32 is set to the height that the thread can be released at the rotating position of the thread guard arm 31 exceeding the center line X between the operation position and retreat position and at the position apart from the traverse center line X by the distance L.