本稿では、1990 年代後半から2000 年代前半にかけての日本における非伝統的金融政策 のあり方を概観すると同時に、信用緩和政策という観点から再検証する。「流動性の罠」 のもとで有効な政策として、（I）将来の政策の予想のコントロール、（II）バランスシ ートの規模の拡張、（III）特定資産の大量購入（信用緩和政策）、の３つが提案されて いる。当時日銀が行った非伝統的政策は、モラルハザードを伴いながらも、信用緩和政 策として一定の効果を発揮した。ただし、当時の金融危機は、流動性不足よりも、貸出 の不良債権化が深刻な問題であり、この点では当時の信用緩和政策には限界があった。

Under the financial turbulence, the Bank of Japan (BOJ) had launched a series of unprecedented monetary policies in the late 1990s and the early 2000s. The conventional monetary policies were not effective under liquidity trap. However, some unconventional monetary policies, including zero interest rate, quantitative easing, and credit easing, had important roles in stabilizing the economy. The first is to stabilize long-run expectations through the BOJ's commitment that the policy will continue until deflationary concerns disappear. The second is to maintain the proper functioning of the market so as to avoid disturbance in the short-term money market. The latter part of this paper shows that the second element was successful in stabilizing the short-term money market in Japan in the early 2000s. The credit easing policy was more powerful tool in providing ample liquidity under the Japanese Financial Crisis. However, the unconventional monetary policies caused a variety of moral hazards in the markets. We show that the extreme monetary policy was useful in improving macroeconomic performance with some nonnegligible costs.