The present invention relates to a valve unit for container filling machines, particularly for glass bottle fillers.More particularly, the present invention relates to a valve unit (1), particularly for container filling machines (8), comprising a hollow body (2) in which there is slidably housed a plug (3), wherein said plug (3) is hollow and comprises an outer duct (23) and an inner duct (24) coaxial to said outer duct (23), a probe (28) having a smaller diameter than the opening of said inner duct (24) being coaxially housed within said inner duct (24), characterized in that said inner duct (24) is made of electrically isolating material.