Police said the accident happened at 1.40am on the Chaiyaphum-Nakhon Sawan Road in Ban Khewa district.
Police said Wannapong Ayuyong, 35, was killed when his motorcycle crashed into a concrete rail of a bridge near the Khun Dan intersection.
His aunt, Noonual Saenghuayrai, 68, said Wannapong was returning home after work.