A silicon-germanium (SiGe) heterojunction bipolar transistor (HBT) is disclosed, which includes: two isolation structures each being formed in a trench; a set of three or more pseudo buried layers formed under each trench with every adjacent two pseudo buried layers of the set being vertically contacted with each other; and a collector region. In this design, the lowermost pseudo buried layers of the two sets are laterally in contact with each other, and the collector region is surrounded by the two isolation structures and the two sets of pseudo buried layers. As the breakdown voltage of a SiGe HBT according to the present invention is determined by the distance between an uppermost pseudo buried layer and the edge of an active region, SiGe HBTs having different breakdown voltages can be achieved. A manufacturing method of the SiGe HBT is also disclosed.