An object of the present invention is to improve the accuracy of clustering by avoiding detection of false clusters when automatically clustering points on a scatter diagram. A surface analyzer according to a first aspect of the present invention includes a measurement unit (1-2, 4-8) configured to acquire a signal reflecting a quantity of a plurality of components or elements that are analysis targets at a plurality of positions on a sample (3), a scatter diagram generation unit (92) configured to generate a binary scatter diagram based on a measurement result by the measurement unit, a clustering unit (94) configured to perform clustering of points in the binary scatter diagram using a method of a density-based clustering, and a parameter adjustment unit (93) configured to adjust a distance threshold by utilizing distribution information on a signal value of the components or the elements on either axis in the binary scatter diagram, the distance threshold being one of parameters to be set in the density-based clustering.