Knowledge's effect on behavioral responses in a health crisis has been a point of inquiry in many empirical studies that obtained significant findings. However, a variety of knowledge types has been considered in these studies rarely. This study compared the effect of declarative vs. procedural knowledge on behavioral responses to the COVID-19 pandemic. In addition, we examined whether outrage factors, which refer to perceived risk characteristics that are likely to elicit emotional responses, can moderate cognitive knowledge's effect. Data were collected with a survey conducted five months after the first COVID-19 case was confirmed in South Korea. A total of 1,000 respondents completed questions on the two types of knowledge, risk perception, and health behaviors in the pandemic crisis, and three different outrage factors. The results showed that procedural knowledge on how-to-do something was associated significantly with the health behaviors in the crisis, while the declarative knowledge that involves knowing that "something is the case" was not. Further, the outrage factors moderated knowledge's effect in such a way that procedural knowledge's influence on health behaviors diminished when the respondents perceived that the pandemic was uncontrollable. On the other hand, procedural knowledge's effect increased when the outrage factor of fairness was heightened. The implications are discussed in the context of studies of knowledge's effect and the outrage factors' moderation.