Michael Mann Accidentally Shoots Himself in Leg at Los Angeles Gun Range

7:22 AM PT -- Michael Mann's rep tells TMZ ... "On Saturday, at a gun range, a weapon accidentally discharged while holstered resulting in a superficial injury to film director Michael Mann. He was treated and is being released."

Michael Mann was sent to the hospital after he accidentally shot himself in the leg at a Los Angeles gun range ... TMZ has learned.

Sources tells TMZ ... the "Heat" director -- who is an an experienced target shooter for decades -- had been apparently trying to holster his weapon during target practice at a sanctioned gun range around 4 PM when the firearm went off.

He was later transported by an ambulance to a local hospital ... but thankfully his injury is subcutaneous and minor.

The LAPD confirms the incident to us ... cops and the LAFD responded to The Range LA after reports of the shooting.

They say the victim -- who had no intention of harming himself -- was injured during a training accident when he accidentally discharged a firearm into his own leg.