A heterojunction bipolar transistor includes a collector contact layer constituted by a high-concentration first semiconductor layer of a first conductivity type formed on a semiconductor substrate, a collector region stacked on the collector contact layer, a base layer constituted by a fifth semiconductor layer of a second conductivity type formed on the collector region, and an emitter layer constituted by a semiconductor layer of the first conductivity type formed on the base layer. The collector region is constituted by a second semiconductor layer, a third semiconductor layer of the second conductivity type having an impurity concentration higher than that of the second semiconductor layer, and a fourth semiconductor layer of the first conductivity type having a band gap energy higher than that of each of the first and second semiconductor layers and an impurity concentration higher than that of the second semiconductor layer, and the fourth semiconductor layer and lower than that of the first semiconductor layer, the third semiconductor layer, and the second semiconductor layer are sequentially formed on the collector contact layer in an order named.