A high-frequency discharge lamp includes a coaxial waveguide including an internal conductor and a pipe-shaped external conductor surrounding said internal conductor, and a discharge tube including a ceramic or glass tube having an approximately ellipse spherical bulged part formed in a middle of a longitudinal direction, and both ends pinched and sealed; a conductor assembly sealed and attached to an end of the ceramic or glass tube; and an auxiliary electrode for starting disposed near the approximately ellipse spherical bulged part. A rare gas for starting with 1 atmospheric pressure or more at room temperature together with a light emission substance is enclosed inside of the approximately ellipse spherical bulged part. The discharge tube is inserted conductor assembly end first and held in a top opening of the coaxial waveguide. A high-voltage pulse generated by a high-voltage pulse generator is applied to the auxiliary electrode through a pulse transmission line.