Comic books are immensely popular in Japan, with some fictional characters becoming celebrities or even sex symbols.
Marriage is meanwhile on the decline as many young Japanese find it difficult to find life partners.
Taichi Takashita launched an online petition aiming for one million signatures to present to the government to establish a law on marriages with cartoon characters.
Within a week he has gathered more than 1000 signatures through.
"I am no longer interested in three dimensions. I would even like to become a resident of the two-dimensional world," he wrote.
"However, that seems impossible with present-day technology. Therefore, at the very least, would it be possible to legally authorise marriage with a two-dimensional character?"Befitting his desire to be two-dimensional, he listed no contact details, making it impossible to reach him for comment to explain if his campaign is serious or tongue-in-cheek.
But some people signing the petition are true believers.
"For a long time I have only been able to fall in love with two-dimensional people and currently I have someone I really love," one person wrote.
"Even if she is fictional, it is still loving someone. I would like to have legal approval for this system at any cost," the person wrote.
Japan only permits marriage between human men and women and gives no legal recognition to same-sex relationships.
Japan's fans of comic books, or "manga," sometimes go to extremes.
Earlier this month, a woman addicted to manga put out an online message seeking to kill her parents for asking her to throw away comic books that filled up three rooms.