This study aims to investigate the fatigue life of T-Type fillet welded joints for excavators subjected to bending loads, and also to verify the predicted fatigue life of the welded part using the effective notch stress method. Moreover, this study aims to determine an optimal toe angle of the T-Type fillet welded structure. In this context, the fatigue lives of T-Type fillet welded specimens (SM490A) were measured and the effective notch stress method for predicting the fatigue life of the T-Type fillet welded structure was verified by comparing with the FAT-225 curve of IIW (International Institute of Welding) as was suggested for the current types of welded structures. Considering simultaneously the scattering factor of the welded structure, the stress condition at the toe part higher than the root part, and the stress minimization condition of the toe part, the optimum toe angle at the T-Type fillet welding was identified at 30°. Likewise, the maximum stress (310.5 MPa) when the toe angle was 30° was about 14% less than the maximum stress (354.0 MPa) at 45°, and the fatigue life was improved by about 30%.