With regard to a filament winding device in which a plurality of fiber bundles are simultaneously wound around a liner, a tension detecting portion and a tension adjusting portion are miniaturized, the cost of the tension detecting portion and the tension adjusting portion is reduced, and the tension detecting portion and the tension adjusting portion are easily arranged. Provided is a filament winding device 100 that includes a tension adjusting portion 110 that collectively adjusts tension of a plurality of fiber bundles F unreeled from a plurality of bobbins B and an unreeling failure detecting portion 130 that individually detects the unreeling failure of the fiber bundles F on the bobbins B for each bobbin B.