Komura told the doll, with an unidentified person inside, that he hoped he would widely promote Japanese animated cartoons, or "anime."
"Doraemon, I hope you will travel around the world as an anime ambassador to deepen people's understanding of Japan so they will become friends with Japan," Komura told the blue-and-white cat.
The appointment is part of Japan's recent effort to harness the power of pop culture in diplomacy. Japan also created an International Manga Award last year under comic enthusiast former Foreign Minister Taro Aso, who likened it to a "Nobel Prize" for an artist working abroad.
Manga, the name used for Japanese-syle comic books, often combine complex stories with drawing styles that differ from their overseas superhero counterparts, particularly in their emphasis on cuteness.
This year, the ministry plans to arrange showings of a Doraemon film in Singapore, China, Spain, France, and at other Japanese diplomatic missions around the world.
Doraemon -- through voice actress Wasabi Mizuta, who spoke from behind a sliding paper screen -- promised Komura that "through my cartoons, I hope to convey to people abroad what ordinary Japanese people think, our lifestyles and what kind of future we want to build."
Created by cartoonist Fujiko F. Fujio, Doraemon is a Japanese cultural icon and is popular around the world, especially in Asia. The robotic cat travels back in time from the 22nd century and uses gadgets such as a "time machine" and an "anywhere door" that come out of a fourth-dimensional pocket on his stomach to help his friends, allowing them to travel anywhere and to any time they wish.
Astro Boy, another cartoon icon, was named last November as ambassador for overseas safety.