Morimasa Owaku (大和久 守正, Ōwaku Morimasa, born February 25, 1929) is a Japanese screenwriter. He wrote many episodes of the TV series "Tokuboku Moto Sousa Tai" (Special Mobile Investigation Unit) from 1962 to 1968, and is known for writing the screenplays for the theatrical films "Showa Zankyoden Shinde moramasu" (1970) and "Shin Abashiri Bangaichi Fubuki no Daidassou" (1971), both starring Ken Takakura.