An Edeka store in the southwest German town of Ruelzheim has piloted the technology since November and now the company plans to equip its stores across the region.
"All customers need do is register once with their identity card and bank details, then they can shop straight away," said store manager Roland Fitterer.
The scanner compares the shopper's fingerprint with those stored in its database along with account details.
Edeka bosses said they were confident the system could not be abused.
Fingerprint templates are stored on a local server which manufacturers say cannot be accessed from outside but some consumer groups are concerned about security issues.
"We see the risks that arise from the data-gathering and also the insecurity factor which is inherent in this process, as more serious than the advantages," said Evelyn Kessler, spokesperson of the Consumer Advice Centre in the Baden-Wuerttemberg region.
Source: Fingerprint billing for Germans