The incident took place last night when four unidentified miscreants intercepted a vehicle in which Raj Singh Yadav, his son Pradeep Yadav and son-in-law Deepak Yadav were returning to Badshahpur village of Gurgaon district via Kosli, they said.
The armed assailants asked the occupants to hand over the cash to them, police said.
The money was borrowed by Raj from one of his relatives, they said.
Police has registered a case of robbery, besides slapping provisions of the Arms Act, on a complaint filed by the victim.