Sakari Momoi, a former high school principal who was born on February 5, 1903, received a certificate from Guinness World Records confirming the achievement.
Dressed in a black suit, white shirt and silver tie, Momoi told assembled media at the Tokyo care home where he lives that he did not plan on going anywhere just yet.
"I want to live for about two more years," he said in soft voice.
Momoi bagged the title after the death in June of American Alexander Imich, who was born a day earlier.
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Except for poor hearing, Momoi is in good health and enjoys reading books and watching sumo on television, according to local press.
He was born in Minamisoma, Fukushima, an area that was badly hit by the deadly 9.0-magnitude earthquake and tsunami in 2011 that triggered the world worst nuclear crisis in a generation.
According to Guinness, he moved to Saitama, north of Tokyo, many years ago.
Japan, known for the longevity of its people, was previously home to the oldest man ever to have lived -- Jiroemon Kimura, who died in June 2013 at the age of 116.
The figure, already one of the highest proportions in the world, is expected to rise to around 40 per cent over coming decades.