Ambiguity was divided into semantic and affective ambiguity, and their effects on the aesthetic evaluation of haiku were examined for Japanese and German speakers. 450 Japanese and 373 German speakers evaluated 36 haiku for 10 items. The results showed that as semantic ambiguity increased, the aesthetic evaluation of haiku decreased. As a measure of affective ambiguity, we focused on awe and nostalgia, which encompass both positive and negative emotions, and the more they felt these emotions, the higher the aesthetic evaluation. These tendencies were greater for German speakers than Japanese. The reasons for the effects of two kinds of ambiguity on aesthetic evaluation of haiku and the cultural differences will be discussed.