He was identified as Tameesi Arwae, 43, a resident of Ban Bango Gubo in tambon Borngor of Rangae.
Pol Col Jiradej Phrasawang, chief of Rangae police station, said he received a report of the shooting about 9.30am.
The shooting occurred inside the victim’s rubber plantation at the edge of the village, he added.
According to witnesses, Tameesi was working in the plantation when a gunman fired two shots at him with a handgun. The assailant then fled.
Tameesi took two bullets in his back and died on the spot.
Police blamed separatist militants.