Sakari Momoi, a former agricultural chemistry teacher, became the world's oldest man after his predecessor Alexander Imich in the US died at the age of 111 years and 124 days in June last year.
Momoi who was born on February 5, 1903, in Fukushima city has five children and currently lives in a hospital here.
Momoi responded with a smile as the family helped him celebrate his birthday, his 66-year-old son Hiroo told 'Kyodo' news agency.
Momoi remains active in his old age and participates in some of the hospital's activities such as throwing a ball and practicing calligraphy, according to his family.
According to Guinness World Records, the world's oldest living person is 116-year-old Misao Okawa in Japan. Okawa will celebrate her 117th birthday on March 5.