Ben Affleck's block is a hotbed for all kinds of authority figures lately ... 'cause now the military is hanging outside his Westside L.A. home -- days after cops and FBI agents were seen around the house amid wildfires in the area.

The actor was photographed returning home Thursday ... and, parked just outside his house was a sand-colored military Humvee -- outfitted with a turret to mount a large machine gun if necessary.

Check out the pics ... Ben drives past like nothing's out of the ordinary -- even though a man in uniform is standing outside the vehicle in BA's affluent neighborhood.

Worth noting ... we didn't see Ben interact with anyone outside his Brentwood home -- so, it doesn't seem like Uncle Sam is coming down on the movie star himself.

The National Guard was deployed last week to help amid the Pacific Palisades wildfire, which has burned more than 23K acres and destroyed entire neighborhoods in the Palisades and Malibu.

As you know ... Ben's street has been full of unexpected visitors in recent days. We told you earlier this week FBI agents visited Ben's house to investigate a drone that collided with a firefighting aircraft.

Our sources told us Ben isn't the subject of an FBI probe, so he's not in any danger legally it seems.

A couple days later, photogs spotted Ben in the middle of a tense conversation with police officers ... and, it seems Ben was talking about private security officers giving him a hard time while entering and exiting the neighborhood.

FBI, cops, and now the military ... Ben may want to watch his back, 'cause the CIA may come calling next!