The 23-year-old, who is nominated for WBN’s Young Fighter of the Year for the third year in a row, having won the award in 2014, remained undefeated with a fourth successful defense of his belt.
Inoue has won world championships in two weight classes already in his short career and could move up to challenge for a third in 2017.
In the co-feature, IBF Light Flyweight title holder Akira Yaegashi defeated challenger Wittawas Basapean in the final round of twelve to retain his 108-pound crown.
Yaegashi, 33, was dominant as the three-weight ruler softened up the Thai fighter. He completed the job with just under 50 seconds left.
On the undercard, Ryo Matsumoto halted Victor Lopez in six to push his C.V to 18-1. While light flyweight Ryuji Hara scored an eight-round decision over Hiroya Yamamoto.
Ex-amateur star and super middleweight contender Ryota Murata is still undefeated following a three-round knockout of Bruno Sandoval.
Headliner Inoue watched on as super lightweight cousin Koki Inoue made it six wins on the spin as a pro. He took out Futoshi Usami in the third session.
Featherweight Satoshi Shimizu completed the card by moving to 2-0.
