This study deals with a proposal on the methods for investigating modular sizes of masonry units, components and buildings in historical masonry in Meiji and Taisho era. The methods aim at solving the view of the module at that time on the basis of a series of investigations of brick masonry buildings by proposing the module dimensions which are defined the total sum added joint width and brick product dimensions. The unit module is clarified as a quarter of the module length of masonry units so that the concept of unit module leads to the clarification of the features of modular coordination.
