Does exposure to a like- or non-like-minded information environment lead to political incivility on social media? While a few previous studies have investigated this question, their results have been mixed. There are two conflicting possibilities: (1) if individuals are exposed to a like-minded information environment, their preexisting beliefs are reinforced, and they are more likely to use uncivil expressions, and (2) if individuals are exposed to a non-like-minded information environment, they often feel negative emotions and therefore are more likely to use uncivil expressions. To evaluate these two competing possibilities, the present study collected Japanese political posts from social media X (ex-Twitter) via X API in April 2023 and analyzed them using the number of parties of the politicians that the user followed as a proxy for a non-like-minded information environment. The results of the statistical analysis indicated a very small and non-significant association between a like- or non-like-minded information environment and posting uncivil comments about politics.