The Japanese government has confirmed the economy grew by 1.2 percent between January and March from the previous quarter.
That was unchanged from the initial estimate.
Analysts were thinking that the figure might have to be revised downwards.
The revised figure translates into GDP growth of five percent in real, price-adjusted terms, slightly more than the initial reading of 4.9 percent.
Economists expect growth to moderate in the second quarter with the end of government stimulus packages to encourage people to buy low-emission cars and electronics.