The man, identified as Thanakrit, lived in Mae On district, with the baby after his wife had left him. On May 31, he left his house without his purse and medicine. His father said Thanakrit told him he wanted to calm himself down.
He was found later hanged from a tree in a local forest. His phone, motorcycle and ID card were found at the scene.
The man is thought to have been dead for a week or longer, according to his physical condition.
His funeral was held on Friday (June 12), afternoon.