1. Msgr. CIMATTI, Vincenzo S.D.B. 1935-1940 (Prefect Apostolic)
2. Msgr. IDEGUCHI, Francis Ichitaro 1940-1945 (Administrator Apostolic)
3. Most Rev. FUKAHORI, Dominic Senemon 1946-1961 (Administrator Apostolic)
4. Most Rev. HIRATA, Peter Saburo 1961-1969
5. Most Rev. HIRAYAMA, Peter Takaaki 1969-2000
6. Most Rev. MIYAHARA, Dominic Ryoji 2000-2008

On March 28, 1928, the two prefectures of Miyazaki and Oita were separated from the Fukuoka Diocese and entrusted to Italian Salesian Fathers. On January 28, 1935, it became the Prefecture Apostolic of Miyazaki and Father Vincenzo Cimatti, S.D.B. was appointed the first ordinary. In 1940 Monsignor Cimatti resigned, and Monsignor Ideguchi Ichitaro, Prefect Apostolic of Kagoshima, served concomitantly as Administrator Apostolic of Miyazaki. From 1946 Bishop Fukahori Sen'emon of Fukuoka served concomitantly as Administrator Apostolic of Miyazaki.

On December 22, 1961, the Prefecture Apostolic of Miyazaki was raised to the status of a diocese and became the Diocese of Oita. Father Hirata Saburo was appointed the first Bishop of Oita and was consecrated on March 26, 1962.

On November 15, 1969, Bishop Hirata was appointed Bishop of Fukuoka and Father Hirayama Takaaki was appointed to replace him in Oita. He was consecrated bishop on January 25, 1970.

On June 12, 2000, Bishop Hirayama retired and Nagasaki diocesan priest Fr. Miyahara Ryoji was appointed as his successor. He was consecrated bishop on October 1, 2000.
Due to Bishop Miyahara being named Bishop of Fukuoka on March 19, 2008, and installed on May 18, 2008, the episcopacy is vacant at this time