日本女性董監事制度之研究——以綜合商社為例

Abstract

本文探討日本企業女性董監事制度之發展歷程、實務困境與改革方向。研究首先分析日本上市公司女性董監事數據，指出其比率自 2012 年的 1.6% 成長至 2025 年的 14.0%，此進程係由政府軟法引導、強制資訊揭露及東京證券交易所量化目標所驅動的。其次，本文透過對日本五大綜合商社（三菱商事、伊藤忠商事、三井物產、住友商事、丸紅）的實證研究，發現儘管各公司積極響應政策使女性董監事比率大幅提升，但存在顯著的「職位偏差」：女性高度集中於「外部董事」或「外部監事」職位，而「內部董事」與「內部監事」之女性比例依然幾近於零 。 本文分析認為，上述現象源於日本特有的「應屆畢業生招募」與「終身雇用制」等就業慣例，導致女性在長賽程的升遷體系中因生命階段責任而脫離核心晉升軌道，形成結構性的人才斷層。在法制層面，現行政策僅追求整體數量的達標，忽略了會社法下內外部董監事在職權與資訊取得上的本質差異，導致性別多元化面臨淪為形式象徵之風險 。 基於比較法研究，本文主張日本應從追求女性董監事的「數量」，轉向追求「質量」的實質平等。本文建議參考台灣經驗，透過東京證券交易所的「有價證券上市規則」或「公司治理準則」進行規範，引入「女性內部董監事」之階段性比例要求。唯有強制企業從內部拔擢女性進入決策層，方能打破「老男孩俱樂部」的權力結構，實現具備國際競爭力的實質多元治理 。

This thesis examines the development trajectory, practical challenges, and reform directions of the female director system in Japanese corporations. The thesis first analyzes data on female directors in Japanese listed companies, showing that the proportion increased from 1.6% in 2012 to 12.5% in 2024. This growth has been driven by government-led soft law, mandatory information disclosure, and quantitative targets set by the Tokyo Stock Exchange. Next, through an empirical analysis of Japan’s five major general trading companies—Mitsubishi Corporation, Itochu Corporation, Mitsui & Co., Sumitomo Corporation, and Marubeni Corporation—the thesis finds that although these companies have actively responded to policy initiatives and significantly raised their overall proportion of female directors, a pronounced “positional bias” persists. Women are overwhelmingly concentrated in positions as “outside directors” or “outside auditors,” while the proportion of women serving as “inside directors” or “inside auditors” remains close to zero. This thesis argues that this phenomenon stems from Japan’s distinctive employment practices, such as the “new graduate recruitment system” and “lifetime employment,” which cause women to drop out of the core promotion track during long-term career progression due to life-stage responsibilities, thereby creating a structural pipeline gap. At the legal and institutional level, current policies focus primarily on achieving aggregate numerical targets, while overlooking the fundamental differences in authority and access to information between inside and outside directors and auditors under the Companies Act. As a result, gender diversity risks being reduced to a merely symbolic formality. Based on comparative law analysis, this thesis proposes that Japan should shift its policy focus on female directors from a pursuit of “quantity” to a pursuit of “quality,” aiming at substantive equality. The thesis recommends drawing on Taiwan’s experience by introducing phased ratio requirements for “female inside directors and auditors” through the Tokyo Stock Exchange’s Securities Listing Regulations or Corporate Governance Code. Only by mandating companies to promote women from within to decision-making positions can the entrenched “old boys’ club” power structure be dismantled and a form of substantive, internationally competitive, and diverse corporate governance be realized.