He was left holding the bag.

An armored car guard was robbed at gunpoint of more than $13,000 on an Inwood street after he left a dollar store with a sack of cash, only to find his partner had driven off with their vehicle, authorities said.

The guard, 25, had just picked up the money from the Family Dollar on Nagle Avenue near Academy Street at about 5:45 p.m. Wednesday. When he emerged, his supervisor and their armored car were nowhere in sight, police said.

A man then approached the guard, pressed a .357 revolver to his chest and barked, “Give me the money,” according to cops.

The guard, who cops said was unarmed because he was awaiting his pistol permit, handed over the bags containing $13,111, and the gunman jumped into a waiting car, officials said.

Plainclothes officers soon spotted the getaway car heading south on the Henry Hudson Parkway near West 181st Street and pulled it to a stop, authorities said.

A search of the car yielded the stolen bags of cash, a .357 revolver with 21 spare rounds of ammo, and several bags of heroin, according to police.

The suspected gunman, 59, and his driver, 38, are in custody and charges are pending, officials said.

Cops are also talking with the driver of the armored car, who works for Safe and Sound Armed Courier, to figure out why he ditched his partner at the dollar store, cops said.

He was found a short time after the robbery sitting in the truck at Broadway and West 181st Street, more than a mile from the dollar store.