Hirokazu Nagai (長井 弘和, Nagai Hirokazu, born November 10, 1968), better known as Mitsuya Nagai (長井満也, Nagai Mitsuya), is a Japanese mixed martial artist, professional wrestler and former kickboxer. A professional MMA competitor from 1991 until 2013, he fought the majority of his career in Fighting Network RINGS. Once a student of legendary professional wrestlers Satoru Sayama and Akira Maeda, Nagai holds notable victories over former King of Pancrase Super Heavyweight Champion Tsuyoshi Kosaka, Nobuaki Kakuda, four-time world kickboxing champion Andre Mannaart, Russian sambo champion Mikhail Ilyukhin, RINGS King of Kings 2000 Tournament runner up Valentijn Overeem, ADCC bronze medallist and RINGS Light Heavyweight title contender Chris Haseman, and Pancrase veteran Takaku Fuke. He also fought for K-1 in kickboxing.
He later transitioned to traditional puroresu and notably wrestled for Battlarts, New Japan Pro-Wrestling (NJPW) and All Japan Pro Wrestling (AJPW), where he is a former three time All Asia Tag Team Champion. He currently performs on a part-time basis and has competed for shoot style and MMA promotion GLEAT and Pro Wrestling Noah.