Officials said the economy expanded 0.9 percent from the previous three months, instead of 0.6 percent quarter-to-quarter as was previously estimated. The earlier estimate, provided Aug. 12, translated to an annualized growth rate of 2.6 percent.
The faster growth rate should further encourage the government of Prime Minister Shinzo Abe to increase the sales tax next April to 8 percent from the current 5 percent, observers said.
The news came after it was announced that Tokyo would host the 2020 Summer Olympics, which would benefit the economy by giving a boost to tourism and the construction industries, Kyodo News reported.
There was a sharp upward revision in capital spending.
Business investment spending grew 1.3 percent.
Japan has also had higher exports and increased consumer spending, all critical to lift the economy out of 15 years of deflation.
"Corporate performance was confirmed to be improving as business investment turned positive," Mitsumaru Kumagai, chief economist at the Daiwa Institute of Research, told Kyodo.
"The April-June revised GDP data, considered a key indicator for a decision on the consumption tax hike, suggested it will be implemented as planned."
"I honestly think [the growth rate] was better than I expected ...The prime minister will make a judgment [on the tax matter], taking this into account," Chief Cabinet Secretary Yoshihide Suga told a news conference.
The new growth rate follows a 4.1 percent growth in the January-March quarter and 1.1 percent expansion in the last three months of last year.