Police stopped a vehicle driven by the two suspects, aged 29 and 35, in the town of Poysdorf in Lower Austria, where they found the counterfeit money hidden behind the fabric of the car door, Austrian national broadcaster ORF reported.
The BK said Austrian authorities had been on the trail of the counterfeiting ring for several months, and believed the money was intended for use within Austria.
In cooperation with German authorities, the 38-year-old gang leader and an accomplice were arrested in the German city of Hamburg.
Police also found the counterfeiters' workshop including printer, paper and newly-printed counterfeit bills.
Three of the four suspects are from Serbia, and the fourth is Romanian.
Austrian police said the investigation into the ring is continuing, but could not confirm the quality of the fake bills or say how many of them are already in circulation.