According to the Konan Police Station, Takashi Anbe, an officer at the Chugoku-Shikoku bureau, paid 15,000 yen to the girl, 17, to perform illicit acts inside a private room at a manga kissa cafe in Toshima Ward.
Anbe, who has been charged with violating child prostitution and pornography laws, admits to the allegations.
The suspect met the girl through a deai-kei matchmaking site.
The incident emerged during a routine cyber patrol conducted by the station.