A muscle-bound intermediate school gym teacher at an Astoria school who moonlights as a professional bodybuilder was busted for being a loan shark.

Sean Harris, 36, of East Meadow, was arrested last night in Nassau and released without bail early Wednesday morning, authorities said.

Harris was charged after he lent someone $40,000 at 2% interest per week last year, which amounts to a sky-high annual interest of 104% — or more than four times the legal limit.

Other charges currently pending against Harris include a June 2010 rap for possessing steroids, and photos show the bulky Harris as tanned and ripped.

“This defendant was trusted to educate children and serve as a positive role model in their lives, but instead he conducted himself like a common criminal,” Nassau County DA Kathleen Rice said.

Harris is charged with criminal usury and faces up to 4 years in prison if convicted.