Depending on the pilot project's success in Japan it could be rolled out to the firm's headquarters and overseas, a Fast Retailing spokesman told NBC News.
The program is aimed at attracting and retaining talent — particularly women, according to the firm.
"We've got a big program at the moment, working towards empowering women in the workforce," the spokesman said. "The idea is that if you've got kids, it gives you a lot more flexibility."
Fast Retailing's decision mirrors that of other firms which have recently announced moves designed to keep workers happy by offering them a better work-life balance.
Earlier this month, online video streaming company Netflix offered employees unlimited maternity and paternity leave for up to one year. The idea behind this move, the company said, was that "continued success hinges on us competing and keeping the most talented individuals in their field."
A day later, Microsoft unveiled enhanced parental leave and other benefits for its employees.
In contrast, online retailer Amazon came under fire this week after aNew York Times story that depicted a harsh, grueling and competitive work environment that made little effort to accommodate employees' personal lives.