Police will allege the boy walked into a tobacco shop on Melville Road in St Clair at 8.45pm and demanded money and vapes before he threatened a shop attendant with a knife.
Detectives said the boy left the store with vapes and an energy drink and the employee was not injured.
Police will then allege that more than an hour later, the same child demanded cash and cigarettes at a service station on Banks Drive in St Clair before he threatened a worker with a knife.
He left the store empty handed and the employee was not injured.
Police arrested a boy near Alpine Circuit in St Clair and took him to Penrith Police Station.
He was charged with robbery armed with offensive weapon and demand property with menaces with intent to steal.
The boy was denied bail to appear before Parramatta Children’s Court today.