In Japan, the "Recommendation for Loads on Buildings" standard is usually used to evaluate the wind loads on buildings and the corresponding response. This standard includes a formula for predicting the standard deviation of response displacement, and the value of the power spectral density of the input wind force at the natural frequency building. However, since the fluctuation of the power spectral density of the input wind force is large relative to the change in the frequency, the predicted standard deviation of the response displacement may be sensitive to small changes in the building's natural frequency. The purpose of this study is to clarify the effect of smoothing of the wind force power spectral density on the accuracy of the predicted wind response.