This paper evaluates the impression of questions and answers at Q & A sites in order to avoid the problem of mismatch between the questioner and the respondent. First, 50 impression words effective in evaluating impressive expression of statements are selected from a dictionary in order to measure the affinity of the question to the response so that we could match them properly. We then conduct an impressive evaluation experiment for 60 question and answer statements posted at Yahoo! Chiebukuro by using those impression words. Nine factors are obtained by applying the factor analysis to the scores obtained through the experiment. Lastly, the best answers, which are decided by questioners, are tried to be estimated by using the factor scores.