Now even his prosecutors agree: the former Lehman College philosophy adjunct professor accused of entering St. Patrick’s Cathedral carrying cans of gasoline last April is mentally unfit for trial.

The attempted arson charges against Marc Lamparello, of Hasbrouck Heights, NJ, will be put on hold indefinitely while he gets treatment in a mental health facility, a Manhattan judge ruled Thursday.

Lamparello, who is currently jailed at Rikers, will return to court on July 16, when the judge will formally order him committed.

Lamparello was arrested at the cathedral in April, days after Notre Dame Cathedral in Paris suffered major damage from an electrical fire.

He admitted to cops that he’d gone off the medications he takes for schizophrenia and bi-polar mood swings; prosecutors found that he had cased the cathedral the day before.

“It’s very clear to us … that his plan and intent on the night of April 17 was to burn down St. Patrick’s Cathedral,” prosecutor David Stuart said at Lamparello’s arraignment.

Defense lawyer Chris DiLorenzo, has blamed his client’s behavior on a psychotic episode.

Prosecutors had initially challenged the finding that he was unfit for trial; on Thursday they did not contest the latest finding.

With Post wires