Rothley Post Office, which villagers said was due to close in four days, was targeted at about 03:40 GMT on Tuesday.
Leicestershire Police said a forklift-type vehicle - believed to have been stolen from a nearby building site - was used to smash the shop.
The suspects then made off with the machine in another vehicle.
This vehicle was later found burned in a field in Belton, Rutland.
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Commenting on the raid, a local coffee shop tweeted there were "unbelievable scenes" in the village, north of Leicester, saying the post office had been "gutted".
Police are appealing for witnesses.
A post office has been left "gutted" after a cash machine containing up to £30,000 was torn out of the shop front during a ram-raid.