Criminal papers against the 23-year-old man and three other people who helped organise the event were sent to the Tokyo district public prosecutors’ office, the Metropolitan Police Department (MPD) said, without naming them.
But police did not question the dishing out of the genitals, possibly because there is no law against cannibalism in Japan.
The man had earlier identified himself as Mao Sugiyama and an “asexual” illustrator.
In an email to AFP in May, he confirmed the event had taken place and said it was organised to raise awareness about “sexual minorities, x-gender, asexual people”.
An MPD spokeswoman said that the four people conspired to “openly display the (illustrator’s) severed male genitals to the assembled 71 guests” at a music club from 7 pm to 10 pm on May 13.
“Every one of them has admitted that they did it,” she said.
If convicted of indecent exposure, a crime known as the display of obscene objects in Japanese, they can be jailed up to two years and/or fined up to 2.5 million yen (US$32,000) each.
In tweets on May 18, the artist said steps were taken so his act met all relevant laws, including a ban on organ sales, processing of medical waste and even food sanitation requirements.
Sugiyama said his penis and testicles had been surgically removed by a physician in March and certified free of infections. They were kept frozen for two months before the event in Suginami, a residential area in western Tokyo.
Diners each paid 20,000 yen (US$250) for a portion.
The police probe followed a complaint from the mayor of Suginami.
“Many residents of Suginami and elsewhere have expressed a sense of discomfort and feeling of apprehension over this,” Mayor Ryo Tanaka said in a statement.