Two men wearing Halloween masks threatened staff with a hammer and a knife before stealing cash from a Co-op store.
Leicestershire Police said the armed robbery took place at 21:30 BST on Thursday in West End, Barlestone.
The two robbers have been described as about 6ft tall and wearing dark clothing.
The force added none of the staff were injured and no arrests have been made yet.
A member of the public who entered the store at the time sustained an elbow injury that did not require hospital treatment after being pushed to the floor.
A Co-op spokesman said staff were "obviously shaken" and that they are supporting police in their inquiries.