In the field of life sciences, biotech start-ups are expected to follow a more rapid commercialization process than that experienced by big pharmaceutical companies. There are about 300 public companies out of 1500 biotech start-ups in the United States, but only 23 public companies out of about 500 biotech start-ups in Japan. Why is there such a big numerical difference between the two countries? As a key term, a timing option is defined as a deferrable right—like a call option—to start any given project as a real option. It is considered as a useful tool when determining the optimal timing for risky, but promising biopharmaceutical projects given the trade-off of irreversible investments as a sunk cost. The objectives of this paper include determining the characteristics of the optimal timing for start-ups, understanding the model structures, and forecasting the optimal timing. As one of findings, the dividend as an opportunity cost of waiting option can be more important than the risk and the intensity of R&D competition. It means that Japan’s start-up environment as venture capital or partnership opportunity with big pharmaceutical firms needs to be improved.