In wind resistant design of long-span bridges, their behavior against the wind are evaluated through wind tunnel tests or analytical approaches. A little evidence has been reported so far whether or not wind properties acting on bridges are the same ones as assumed in the design code and they behave in the same way as assumed in it. This paper presents the result of the study on the validity of wind resistant design for long-span bridges based on the field observation results of the Ohnaruto Bridge and the Minami Bisan-Seto Bridge. The possibility that the wind load for long-span bridges could be reduced is suggested by reconsidering the spatial correlation of the wind.