This research aims at rationalization of the selecting technique of a crack repair method of construction with the movement occurred in RC structure. The definition of "existence of crack width behavior" of the flow chart in the public organization's specifications for crack repair method selection is so ambiguous. In this research, behavior of the crack produced in the outer wall of an actual building was measured, and new knowledge was able to be acquired about the opening-and-closing pattern and crack width behavior of cracks which were produced in the outer wall of building. Although it was generated in the building of only one building, and the cracks and consideration in this paper are based on this measurement results, it was thought that the results of this paper has the flexibility about the crack investigation for selection of a repair method of construction.