Men armed with crowbars entered a Wetherspoon restaurant in Batley this morning and made off with cash from gambling machines.
An engineer was emptying the machines at around 6.45am when the men entered the premises and threatened staff.
A Wetherspoon spokesperson said: “Staff are thankfully all OK, but were shaken by the incident.
“The pub has since reopened following investigations by the police.”
A West Yorkshire Police spokesperson said: "Police were called to a pub on Hick Lane, Batley at about 6.51am this morning to reports of a robbery.
"It took place after a group of males entered the property and threatened staff.
"Initial enquiries are ongoing into the incident and no injuries have been reported.
"Anyone who has information about what took place is asked to contact Kirklees CID on 101 referencing police log 2039 of March 1."
Wetherspoons have been approached for official comment.