The robber entered the Ladbrokes store in Gorgie Road at 3pm on Tuesday and pulled a knife before demanding money from the till.
He is described as white, 25-30 years old with short hair and a freckled complexion. He was wearing a light-coloured hat with a dark band, Burberry-type scarf, green jacket, blue jeans and white trainers. He made off down Westfield Road with a three-figure sum of cash.
A police spokesman said: “This was an incredibly frightening experience for the store worker, who was alone within the premises at the time of the robbery and we are keen to speak to anyone who can assist us in identifying the man responsible.”
Anyone with information should call police on 0131-311 3131.