In a construction of electrode for a high pressure discharge lamp used with maintaining a high input of electricity, which discharge lamp comprises a valve composed of a luminescence tube having a swelled portion at the middle thereof, and an anode and a cathode placed opposite to each other, the cathode is composed of a metal with a high melting temperature doped with a electron-emitting substance and having a tapered portion toward the discharge side, the slope portion of said tapered portion being subjected to carburization at said tapered portion, and a non-treated portion being formed at the edge of the tapered portion continuous to the carburized portion.