In a filament winding apparatus, a supplying device supplies fiber bundles to a surface of a core material. A moving part is movable relative to the core material, and rotatable around a rotational axis extending in a vertical direction. A small diameter aligning guide part is placed at the moving part and has an opening portion through which the core material can pass. The small diameter aligning guide part guides fiber bundles to an outer peripheral surface of the core material such that the fiber bundles are arranged side by side in a circumferential direction of the core material. The tightening fiber bobbin supporting part is placed at the moving part and rotates around a center of the opening portion. A winding guide rotates with the tightening fiber bobbin supporting part and guides a tightening fiber bundle drawn from a tightening fiber bobbin toward the surface of the core material.