Michael Bay is going to need some costly home repairs … because cops say someone drove a car into his front gate and caused six figures’ worth of damage before fleeing the scene.

Law enforcement sources tell TMZ … the LAPD responded to the famous director’s Los Angeles area home Tuesday morning for a hit-and-run involving his property.

Cops were called after a Bay employee discovered a car had damaged the front gate, snapped a tree in half, knocked over a city sign and took out the gate keypad.

Sounds like one hell of a wild ride … and TMZ obtained photos of the aftermath, showing the trail of destruction on the edge of Michael’s estate.

We’re told cops found car debris among the wreckage, and they took a report for hit-and-run/vandalism.

The initial cost of the damage has reportedly been estimated at $100,000.

Unclear when this car came barreling past the entrance to Michael’s home, but cops say the accident happened sometime within the last 24 hours … though it doesn’t appear Michael was home at the time.

LAPD says there have been no arrests so far, but they are investigating … and police believe this could have been the work of a drunk driver.