It will allow the government to borrow additional money by selling bonds to pay for a large chunk of its expenses.
The approval comes amid fears that Japan's economy may be heading towards a recession.
The opposition had previously delayed the bill, demanding that the government call for elections first.
On Friday, Prime Minister Yoshihiko Noda dissolved the parliament, paving the way for snap elections to be held next month.
In a separate move, Japan's government warned that the economy is showing "signs of weakness", adding to concerns about the health of the world's third-largest economy.
It said that industrial production is falling and exports continue to remain weak due to slowing global demand.
It added that private consumption and business investment also remain subdued.
Japan's economy shrunk 0.9% in the July to September quarter, from the previous three months, and there are fears it may contract further in the current quarter.
"Concerning short-term prospects, weak movements would remain for the time being," the Cabinet Office said in its monthly report.
This is the fourth successive month that Japan has lowered its assessment of the economy, the longest such streak since the 2008 - 2009 global financial crisis.
One of the big concerns among policymakers in Japan has been continued deflation, or falling consumer prices, in the country.
That has hampered their efforts to boost domestic consumption as consumers tend to put off purchases in hopes of getting a better deal later on.
Consumer prices in Japan fell 0.1% in September, from a year earlier, the fifth straight month of decline.
The government said that it "strongly expects the Bank of Japan to continue powerful monetary easing" to help fight deflation.
Meanwhile, Shinzo Abe, the leader of the main opposition party, the Liberal Democratic Party, has said the central bank needed to set an inflation target of 3% instead of its current 1% goal to help revive growth in the economy.
Mr Abe, who's party is widely expected to win a snap election, has said that if elected, he will put pressure on the bank to ease its policies further and has called for it to print "unlimited yen" to help fight deflation.
His comments have had an impact on the financial markets.
The yen has fallen to its lowest level against the US dollar in six-and-half-months. It was trading close to 80.97 yen against the US dollar in Asian trade.
Japan's Nikkei 225 index rose 2.2% to 9,024.16 points.
Japan's lawmakers have approved a crucial bill that will ensure that the government does not run out of money at the end of this month.