While the chairman of the Tokyo Medical Association, Haruo Ozaki, has recommended the use of ivermectin on COVID-19 patients, neither he nor the organization is associated with the Japanese government.
Just like here Japan has it's outlier quacks.
https://www.politifact.com/factchecks/2021/sep/14/instagram-posts/japan-has-not-approved-ivermectin-covid-19-treatme/