This study provides site-specific profiles of asparagine-linked and serine/threonine-linked glycosylations on ErbB2, a therapeutic target RTK for ErbB2-positive cancer, through structural analysis of recombinant ErbB2 extracellular region and endogenous ErbB2 from ErbB2-positive breast cancer cells. Furthermore, comparison of the N-glycosylated structures of the extracellular regions of ErbB2 and its homologue, the epidermal growth factor receptor (EGFR), showed differences in the distribution and density of N-glycans on both molecules, providing new insights into the different activation mechanisms of ErbB2 and EGFR from a glycan perspective.