Nagasawa was born in Tokyo in 1923. He studied composition with Yasuji Kiyose and graduated from the Faculty of Arts, Nihon University. He was one of the founding members of Pro Musica Nipponia (1964). Since 1949, he has been the musical supervisor for the puppet theater "Puk." In 1986, he composed music for the Kabuki theater production of "Yamato Takeru," starring the famous Kabuki master Ennosuke Ichikawa. He received the Purple Ribbon Medal from the Japanese government in 1990. Nagasawa has joined six overseas tours of Pro Musica Nipponia and serves as one of its honorary representatives. He has written numerous works for Japanese instruments.