Equal rights to work between men and women are recognized as fundamental human rights by many international conventions including the United Nations Convention on the Elimination of All Forms of Discrimination Against Women and the International Covenant on Economic, Social and Cultural Rights. Also, constitutions of many countries recognize equal rights to work as basic constitutional rights. But women all over the world still face numerous kinds of sex discrimination, including direct sex discrimination and indirect sex discrimination, especially in working life. Indirect sex discrimination against women in working life undermines women’s equal rights to work in a covert way, which is just as harmful as direct sex discrimination and should be prohibited by law.