Costa Coffee has been granted permission to open a branch in Teignmouth.
Councillors voted 17-4 in favour of the firm's application.
Local shop owner Thomas Free claims jobs and livelihoods in the resort will be lost when Costa arrives.
He told the planning committee the seaside town has 26 coffee shops and 92 outlets where coffee is served.
Costa said their brand attracts more customers into towns like Sidmouth and Honiton.
More than 1,500 people signed a petition against Costa's plans for Teignmouth.