As widely expected, the central bank kept monetary policy steady and maintained interest rates at a range of zero to 0.1 percent by a unanimous vote.
Japan's economy is gradually emerging from the current deceleration phase, the central bank said in a statement after the rate review.
That compared with the previous month's assessment that while the economy was showing signs of a moderate recovery, growth seemed to be pausing.
The central bank also revised up its assessment on exports and production, saying they are showing signs of resuming an uptrend on accelerating growth in the global economy.
Governor Masaaki Shirakawa will hold a news conference with his comments to come out sometime after 4:15 p.m. (0715 GMT).
Markets will scrutinize his comments for hints on how the recent spike in commodity prices could affect the BOJ's price outlook and the fragile economy.
The BOJ last year cut interest rates effectively to zero and set up a 5 trillion yen ($60 billion) pool of funds to buy assets ranging from government bonds to private debt, aiming to support a fragile economy and pull Japan out of deflation.
BOJ officials have said topping up the asset buying plan is a clear option if downside risks to growth materialize, although expectations of an imminent monetary easing have diminished on growing signs that Japan will soon emerge from a lull.
(Reporting by Leika Kihara and Rie Ishiguro; Editing by Edmund Klamann)