A mystery man was discovered laying lifeless next to a gun on a driveway of a Queens home with a gunshot wound to the head, cops said.

The victim, who was not known around the neighborhood, is believed to be in his 20s or 30s and was found just before 11 p.m. yesterday outside a home on 109th Avenue near 227th Street in Cambria Heights, authorities said.

Although a gun was spotted next to the body, cops said it was unclear if the man committed suicide or was murdered.