1. A mass analysis data processing method for processing data collected by performing a mass analysis on each of a plurality of micro areas set within a two-dimensional area on a sample, comprising: a) a first step for extracting a maximum intensity and a mass-to-charge ratio giving the maximum intensity for each micro area, based on mass spectrum data corresponding to the micro area; b) a second step for extracting a largest value of the maximum intensities of the micro areas obtained in the first step, for determining a color scale for displaying the intensity based on the largest value, for assigning a color to each micro area according to the color scale, the color corresponding to the maximum intensity obtained for each micro area in the first step, and for creating and displaying a colored two-dimensional image corresponding to a portion or entirety of the two-dimensional area; and c) a third step for creating a maximum-intensity spectrum showing a relationship between the maximum intensity obtained for each micro area in the first step and the mass-to-charge ratio giving the maximum intensity, and for displaying the maximum-intensity spectrum in conjunction with the colored two-dimensional image in such a manner that at least a portion of a peak having an intensity value corresponding to the largest value of a plurality of maximum intensities given by a same mass-to-charge ratio is shown using the color associated with the peak in the color scale.