Optical imaging technologies improve clinical diagnostic accuracy of early gastric cancer (EGC). However, there was a lack of imaging agents exhibiting molecular specificity for EGCs. Here, we employed the dye labeled human heavy-chain ferritin (HFn) as imaging nanoprobe, which recognizes tumor biomarker transferrin receptor 1 (TfR1), to enable specific EGC imaging using confocal laser endomicroscopy (CLE). TfR1 expression was initially examined in vitro in gastric tumor cells and in vivo through whole-body fluorescence and CLE imaging in tumor-bearing mice. Subsequently, dye labeled HFn was topically applied to resected human tissues for EGC detection. CLE analysis of TfR1-targeted fluorescence imaging allowed distinction of neoplastic from non-neoplastic tissues (P b 0.0001), and TfR1 expression level was found to correlate with EGC differentiation degrees (P b 0.0001). Notably, the CLE evaluation correlated well with the immunohistochemical findings (κ-coefficient: 0.8023). Our HFn-nanoprobe-based CLE increases the accuracy of EGC detection and enables visualization of tumor margins and endoscopic resection.