Officers accused Yuka Sakaguchi, the 37-year-old proprietor of King & Queen, located in Yao City, and the girl, a third-year high school student, of operating a business without a license.
Both suspects have reportedly admitted to the allegations.
According to police, Sakaguchi did not make appearances at King & Queen. Instead, the day-to day-operations of the lounge were the responsibility of the girl. The lounge also employed three other female teenagers, aged 16 and 17.
Police are now considering adding charges related to the unlawful employment of minors.
The matter came to light after a parent of one of the girls lodged a complaint with law enforcement.