Numeracy is defined as the ability to understand and use mathematical and probabilistic concepts, and one of the central components of risk literacy. However, there were not so many studies about the effect of numeracy on fear after risk information was provided. This study conducted a nationwide online survey to investigate the effect of numeracy on fear when providing information about risk comparison: a method to compare same risks at different times. The reason why risk comparison was used is that it is one of the methods for communicating risk as probabilistic concept. Results showed that people with higher numeracy more decreased their fear after the level of risk decreased, while people with lower numeracy increased their fear. These results were obtained with two materials about radioactive substances in food and Tokyo inland earthquake.