The Muang Trang police were alerted to the suicide of Pluem Chairat at 8:35am.
He was found with a gunshot wound on the left side of his head and a homemade sawn-off shotgun was found beside his body.
His daughter-in-law, Siyamol Chairat, 43, told police that Pluem was earlier a lively man but he later suffered from multiple ailments, including diabetes, hypertension and cancer.