This study clarifies that a home base without mass production activities can support foreign factories by acting as a mother factory through the case of Minebea Co., Ltd. Minebea's home base has aggressively gathered information on mass production from their foreign factories and has continued to accumulate knowledge on mass production, even after discontinuing its own mass production activities. Although the home factory is inactive in terms of mass production, it has succeeded in supporting mass production at their foreign factory as a “knowledge-intensive mother factory,” the factory that possesses knowledge on mass production without engaging in any mass production activity. It was found that a home base can possess knowledge that exceeds its boundary of activities, enabling it to act as a mother factory supporting mass production at foreign factories without engaging in any mass production.