This study formulated the question, “what knowledge do entrepreneurs think they need?” and examined not only concrete knowledge about markets and technologies but also abstract knowledge such as schemas as learning tasks for entrepreneurs. Then, focusing on knowledge, we quantitatively and qualitatively analyzed 96 interviews of Japanese entrepreneurs published in newspaper articles. As a result, along with the knowledge about opportunities and capabilities often discussed in previous studies, we identified a third category and classified it into two categories: attitudes and principles. The former refers to the attitude or mindset that entrepreneurs consider desirable when managing their business, and such ideals are thought to raise the awareness of entrepreneurs. The latter refers to the hypothesis that entrepreneurs have about the causal relationship between X and Y. This hypothesis is thought to underpin the behavior of entrepreneurs who should make decisions in highly uncertain situations. This study suggests that the images and phrases contained in such acquired knowledge may be a source of emotional energy, disciplining and encouraging entrepreneurs.