The Peter De Wint pub at the junction of Moorland Avenue with Tritton Road has been burgled and damaged in the early hours of Tuesday, March 8.
Police say at about 2:55am offenders broke into the premises, causing damage and attacking the Fruit gaming machine. An amount of cash was stolen.
A victim heard banging and saw shadows on the CCTV monitor and called police at 02:55am.
Police say they arrived on scene at 02:56am but the offenders had gone.
Lincolnshire Police would like to hear from anyone who saw or heard any suspicious activity in or around the pub during the early hours of Tuesday.
Anyone with information is asked to contact PC 855 Steven Parker at Boultham Park Police Station. on 0300 111 0300 quoting incident 18 of 8th March 2011.
Alternatively, call the charity Crimestoppers anonymously on 0800 555111.