Not only specialists but also ordinary people have interests in the stock price changes. The present paper analyzes the influence of the frequency of characteristic words that appear in the investor relation (IR) documents of companies. Is it true that the positive words cause the rise of a stock price, and the negative words cause the fall? We focused on 57 medical-supplies-related companies which have listed on Tokyo Stock Exchange. The stock price data and IR documents of the period in 2009 to 2011 were collected. We prepared 10 positive words and 10 negative words to evaluate the score of IR documents. The rate of the stock price compared with the previous day and the document score was analyzed. It is confirmed that the correlation of the rate and the document score is higher for the companies with high stock price ratio of change. © 2012 IEEE.