We are developing an artificial stock market model with investor agents in order to analyze characteristics of a market price. In this paper, we analyze the effects of agent’s reaction rate to technical indicators in a financial market. Intensive experiments have suggested that trend follow investor tends to change his reaction rate frequently to increase his wealth. Moreover, we could get positive return using proper technical indicators in a given artificial stock price path. Based on these results, we propose a simple price estimation method in a real financial market.