This study investigates the relation between contingencies and the effect of ego-involvement on causal reasoning in causal situations. In an experiment, participants were informed about their tasks that involved causality, and they were randomly assigned to four conditions: medium contingency without ego-involvement, medium contingency with ego-involvement, high contingency without ego-involvement, and high contingency with ego-involvement. Thereafter, they were asked to rate the strength of the causality of two events. The result showed that the effect of ego-involvement was clear only when the contingency was high: when ego-involvement was present, the causal relationship was judged stronger than when it was absent. This is similar to the result of an experiment in which contingency was considered as a within-subject variable. The result confirmed that ego-involvement affects causal reasoning when the contingency is high.