PURPOSE: To remove minute bubbles in filled liquid by a method wherein a bubble separator which sucks out gas or air contained in product liquid is arranged just before a measuring and filling part which measures processed product liquid and at the same time fills it into containers.

CONSTITUTION: A bubble separator 15 which sucks out gas or air contained in filled liquid is arranged just before a measuring and filling part 9. The separator 15 has an inlet 16 and an outlet 17 of the filled liquid and a pump connecting port 18 which communicates with a vacuum pump 23, and inside of the separator 15, many hollow systems 19 are bundled. The hollow system 19 is made of polyprophylene or polytetrafluoroethylene and its liquid passage 20 is about 50-300μm. When the filled liquid is made to flow through the liquid passage 20 at a velocity of 5-50cm/sec, minute bubbles 21 coexisting in the filled liquid are separated through minute holes 22 formed in the hollow systems 19 and removed by the vacuum pump 23.