AbstractThe buckling modes of wide flange beams are classified as lateral buckling and local buckling. AIJ Recommendations for Stability Design of Steel Structure [1] for these buckling modes are based on elastic buckling strength. It is therefore important to understand the elastic buckling strength and buckling modes of wide flange beams. The current design specifications make provisions based on simple stress states such as uniform compression and pure shear stress. For long‐span beams, which are currently used in many structural members, dead loads dominate in short‐term loading. However, few studies have considered stress changes due to distributed loading, and the specifications do not adequately consider actual design situations. The aim of this study is to determine the elastic local buckling strength of the web of wide flange beam subjected to uniformly distributed load and end moments. The subject is the web with 4 edge fixed support and the analysis method is a theoretical analysis using the energy method. By considering the difference between the maximum positions of bending stresses and shear stresses, the buckling strength and buckling mode could be correctly determined. The shear buckling coefficient enabled a unified classification of the buckling modes.