Police have now confirmed that the robbery took place at the Spar in Princes Square, West Looe at 10.01 this morning.
The man brandished a two foot long machete at frightened staff before stealing around £100 cash.
He was white, around 5ft 10ins tall, slim wearing a blue shirt, beige baseball cap and a mask.
If anyone witnessed this please contact the police on 101 quoting log 24 of 12 October.