Following his third positive test, taken on Tuesday, the office in Brasilia issued a statement saying the head of state was nevertheless "in good condition."
"President Jair Bolsonaro continues to be in good condition, accompanied by the presidency's medical team. The test taken by the president yesterday, (July) 21, resulted positive," said the statement.
On July 7, Bolsonaro announced he tested positive for the coronavirus after presenting a fever and malaise, and he has been working from his residence ever since, attending no public events.
He tested positive again last week.
Bolsonaro, 65, falls within the demographic considered to be at risk of suffering from COVID-19 complications.
Brazil on Wednesday saw a record 67,860 new cases of COVID-19 in the past day, bringing its total caseload to 2,227,514.
According to the Health Ministry, the new one-day record by far eclipsed the previous one set on June 16 of 45,241 new cases.
The country's COVID-19 death toll rose to 82,771 after 1,284 more patients died in the same 24-hour period.
Another 3,795 deaths are suspected of being related to COVID-19 but have not been verified, the ministry said.
Brazil has the world's second-largest COVID-19 outbreak, after the United States, in both the number of cases and the death toll.
Southeast Sao Paulo state, Brazil's most heavily populated state, is the epicenter of the national outbreak.