The skeletons and a further four cremations were uncovered along with various artefacts during construction work at St James’s Place in Cirencester.
Work to create a car park on the former Bridges Garage site has been halted and security beefed up following the discovery.
Cliff Bateman, Cotswold Archaeology project manager, told the Wilts and Gloucestershire Standard: “We may have a very early Roman inhumation (burial) which is quite a revelation at the moment.
“We could be looking at the earliest inhumation cemetery in Cirencester’s history and maybe in Roman Britain.
“It would challenge archaeological preconceptions that cremations were the main source of burial during the early Roman period.”
Richard King, head of property management at developer St Jame’s Place, said: “It’s important to Cirencester so if we have to wait a few extra weeks for a car park while this is done properly then it isn’t a concern to us.”
He added: “It’s created quite a buzz. We had around 90 office staff having a look yesterday in a guided tour.”