The present disclosure provides a High-Purity Germanium (HPGe) detector, comprising: a HPGe single crystal having an intrinsic region exposed surface; a first electrode and a second electrode connected to a first contact electrode and a second contact electrode of the HPGe single crystal respectively; and a conductive guard ring arranged in the intrinsic region exposed surface around the first electrode to separate the intrinsic region exposed surface into an inner region and an outer region. A leakage current derived from the intrinsic region exposed surface of the HPGe detector can be separated from the current of the HPGe detector by the conductive guard ring provided in the surface, thereby suppressing the interference of the surface leakage current.