In a method of manufacturing a reverse-blocking semiconductor element, a tapered groove is formed and ions are implanted into a rear surface and the tapered groove. Then, a furnace annealing process and a laser annealing process are performed to form a rear collector layer and a separation layer on the side surface of the tapered groove. In this way, it is possible to ensure a reverse breakdown voltage and reduce a leakage current when a reverse bias applied, even in a manufacturing method including a process of manufacturing a diffusion layer formed by forming a tapered groove and performing ion implantation and an annealing process for the side surface of the tapered groove as the separation layer for bending the termination of a reverse breakdown voltage pn junction to extend to the surface.