日本國會常被說是內閣的橡皮圖章，因為不僅內閣提案通過率高，而且內容還很少有被修改，形同國會只是消極地接受內閣提案。但是日本民主黨（以下簡稱民主黨）執政時期，內閣提案通過率平均只有67. 12%，也就是三分之一的內閣法案沒有通過。值得注意的是，儘管內閣推動法案受阻，但是在議員提案部份，不管是在提案的比例及通過率都比以前高。相較自民黨執政時期，民主黨執政時期的議員立法能力的確顯著地提升。明顯地，國會不是如過去所說的空洞化。該如何解釋民主黨執政時期的變化？ 為了要更清楚理解民主黨時期與其他時期不同之處，還得理解立法程序以及過去的議員提案情形，包括提案數、提案類型以及通過的類型，據此提出對民主黨時期議員較好立法能力的可能解釋。因此，本計畫不只針對民主黨政權時期，也回顧過去議員立法情形，以理解議員立法整體之變遷。對於民主黨時期比較好的立法能力，提出四個可能的解釋:是執政黨（也就是民主黨）議員提案的結果（H1）、在野黨積極提案的結果（H2）、委員會提案的結果（H3）、跨黨派提案的結果（H4）。結果發現，主要是與H4委員會主席提案增加有關，並且還與化解民主黨時期立法僵局有些關聯。 The Democratic Party of Japan (DPJ)’s governance presents an interesting case. The DPJ came into power in 2009 with promises to change Japan. However, many policies on which the DPJ campaigned during the 2009 election were either disapproved of or suspended, and the ensuing policy stalemate almost became a landmark of the DPJ government. In contrast to the low passing rate of government bills, it is noteworthy that not only the number of bills introduced by Diet members increased, but the passing rate of bills introduced by Diet members was also significantly higher when compared with the corresponding rates for the Liberal Democratic Party (LDP)-led Cabinets. In terms of agenda-setting and legislative output, the legislative ability of Diet members has been strengthened. What explains this development? Who proposed it? What types of bills were introduced? Did such a development have any relation to the DPJ’s limited legislative ability? Last, but not least, what are the implications for Japanese politics? By reviewing the relevant literature on legislative studies, this project will construct four hypotheses that will be tested to answer the question as to why more bills were passed during the DPJ Cabinet. By using the DPJ’s governance as a case study, this project hopes to provide a better understanding of the rules and procedures regarding how bills become laws and to pave the foundation for future comparative projects.