Japan's health ministry decided on Friday to expand the use of US pharmaceutical company Pfizer's coronavirus vaccine to people aged 12 or older.
The current minimum age for someone to receive the vaccine developed by Pfizer and its German partner BioNTech is 16.
The ministry set the age requirement when it approved the vaccine in February, citing the lack of sufficient data from overseas clinical tests on people aged 15 or younger.
The developers have since conducted tests on adolescents aged between 12 and 15 in the United States.
They say the tests show that the shots are effective and safe for younger people, and submitted additional data to the ministry.
Japan has also approved another vaccine developed by US biotech firm Moderna for people aged 18 or older.
Moderna plans to present the ministry with clinical test data as early as June in the hope of having the minimum age lowered from the current 18 to 12.