A filling system includes a center wheel that conveys vessels, a first filler provided with a plurality of filling heads, a second filler provided with a plurality of filling heads and arranged downstream from the first filler, a first inlet wheel that receives the vessels from the center wheel and supplies the vessels to the first filler, and a second inlet wheel that receives the vessel from the center wheel and supplies the vessels to the second filler. Operation modes are switchable between a first operation mode that conveys the vessels to the first filler and a second operation mode that conveys the vessels to the second filler instead of conveying to the first filler by controlling the reception of the vessels at the first and second inlet wheels.