The teenager managed to pocket "a four-figure sum" after he stormed into a bank in the southern Bavarian town of Bad Füssing brandishing a fake gun and shouting "Hold-up!", local police told AFP.
The boy then raced off on his bike, chased by a witness in a car. He was apprehended by police several minutes later while trying to cross the border into Austria.
He surrendered to officers and admitted to the crime.