The present invention provides a reverse conducting (RC) thyristor of a planar-gate structure for low-and-medium power use which is relatively simple in construction because of employing a planar structure for each of thyristor and diode regions, permits simultaneous formation of the both region and have high-speed performance and a RC thyristor of a buried-gate or recessed-gate structure which has a high breakdown voltage by the use of a buried-gate or recessed-gate structure, permits simultaneous formation of thyristor and diode regions and high-speed, high current switching performance, and the RC thyristor of the planar-gate structure has a construction which comprises an SI thyristor or miniaturized GTO of a planar-gate structure in the thyristor region and an SI diode of a planar structure in the diode region, the diode region having at its cathode side a Schottky contact between n emitters or diode cathode shorted region and the thyristor region having at its anode side an SI anode shorted structure formed by p.sup.+ anode layers, wave-shaped anode layers or anode n.sup.+ layers; in the case of a high breakdown device, an n buffer layer is added; similarly the RC thyristor of the buried-gate or recessed-gate structure has a construction which comprises an SI thyristor of a buried-gate or recessed-gate structure at the thyristor region and an SI diode of the buried or recessed structure.