本文以1080筆在1993年至2010年且在美國市場發行的公司債為樣本,用兩階段最小平方法探討工會強度對公司債到期期限長短的影響。根據先前文獻認為會影響公司債到期長短的因素為控制變數,且根據文獻以兩階段最小平方法來使得槓桿比率及公司債到期長短得以同時被決定。結果發現,工會強度及公司債長短期存在一個顯著為正的關係,表示面對一個強勢的工會,公司會傾向發行長期債券。另外,工會強度對於公司債長短期的影響,也會受公司的狀況左右,當公司的獲利較大、財務狀況較佳或是流動資產增加,都會加強工會對於公司債長短期的影響。We use 1080 bonds and notes issued between 1993 and 2010 in US markets as our sample, and model the two-stage least squares regression to investigate the impact of union strength on the term to maturity. Controlling for previously identified determinates of debt maturity and modeling leverage and debt maturity as jointly endogenous, we find a significant and positive relation between union strength and the term to maturity. Firms under high union strength are likely to issue debts with longer term to maturity. In addition, the impact of union strength on the term to maturity would be affected by the situation of the firm. More profitability, less default risk or current assets increased would increase the impact of union strength on the term to maturity.