The Tokyo Metropolitan Government reported 218 new cases of the coronavirus in the capital on Thursday.
The daily tally has been below 300 for five days in a row.
The figure is down 313 from a week ago, marking a week-on-week decline of more than 50 percent.
The seven-day average up to Thursday is 257.6. The weekly figure fell below 300 for the first time since March 20.
Tokyo officials say 100 patients are in serious condition, seven fewer than on Wednesday.