This paper presents rule discovery from fMRI brain images. The algorithm for the discovery is the Logical Regression Analysis, which consists of two steps. The first step is regression analysis. The second step is rule extraction from the regression formula obtained by the regression analysis. In this paper, we use nonparametric regression analysis as a regression analysis, since there are not sufficient data in rule discovery from fMRI brain images. The algorithm was applied to several experimental tasks such as finger tapping and calculation. This paper reports the experiment of calculation, which has rediscovered well-known facts and discovered new facts.