Identifying the causes of human responses to risk as evolutionary adaptations could explain observations that cannot be explained by rationality or selfishness. For example, human responses to life-threatening risk can be influenced by the effect on other people in addition to the effect on the individual. This could be explained by the concept of inclusive fitness, which accounts for the evolution of altruism. Even if this adaptation could result from the possibility of death and the benefits for reproduction arising from taking risks, it cannot be experimentally demonstrated. Thus, we use an evolutionary multi-agent model where the altruistic agents are evolved in an environment simulating the risk–benefit trade-off between reproductive advantage and death to show that altruism influences the evolved attitude toward risk. The results suggest that risk-averse attitudes are adaptive when the efficiency of the benefit for reproduction is large enough. In contrast, in a harsh environment where the efficiency of the benefit is small, a risk-prone attitude becomes adaptive. The tendency of human beings to evaluate risks that threaten future generations as high could be explained as this kind of evolutionary adaptation rooted in altruism.