That technological diversity plays a key role in business innovation is hardly to be denied. But how is it related to risk? This is the question this paper explores in the context of the medical device industry in Japan. A comparison of two of the largest firms in medical device sector indicates that high‐risk shrinks technological diversity. Conversely, low risk makes it possible to employ more diverse technologies. This difference suggests the hypothesis that successful innovation in high‐risk products and successful innovation in low‐risk products require different management leadership styles, an inference for which a questionnaire survey of a broader sample of firms provides supporting evidence.