The men, aged 19 and 23, were detained on suspicion of plying Ms Furlongs friend, who is also Irish, with alcohol, Kyodo reported.
It is believed one of the men is a high-profile backing dancer.
The men are also being questioned in relation to the suspicious circumstances surrounding the Irish students death, as one of the men was with the student when she was found dead, national broadcaster NHK and Kyodo News said.
They also reported that Ms *Furlong and her friend went back to the mens upmarket hotel after the concert on Wednesday evening.
The agency reported that, in the early hours of Thursday, a hotel guest complained about a loud noise from one of the rooms.
A hotel employee went to the room and found Ms Furlong lying on the floor near the bed and the 19-year-old man standing nearby, Kyodo added.
