There are three purposes in this thesis. First of all, the thesis examines the market herding behavior of real estates in Taiwan. Second, if herding exists in the markets, what factors cause herding behavior? Finally, how does herding behavior affect market performance? The empirical results show there is no herding evidence in the real estates markets when market moves downward. There are different results between different real estates and periods when market moves upward. There is obvious herding behavior in the pre-sale houses in Taipei City. Herding behavior also exist lag phenomenon. During lag period, there is obvious herding behavior in the pre-sale houses in Taipei when market moves upward. There is weak herding behavior in the other real estates, including pre-sale houses of Taipei County, existing houses and land. We find that macro factors such as money supply, GDP growth rate, saving amount, incoming and micro factors such as market depth and market return in the last period will cause herding behavior. Finally, herding behavior, price volatility and transaction amount volatility have Granger causality. Herding behavior will makes price more efficient and increases transaction.