The influence of a high-frequency field in the range of 900–2400 MHz on the lasing power and efficiency of laser radiation with a wavelength of 0.63 μm, applied to the capillary tube of a He-Ne laser with direct-current electrical discharge has been studied. The existence of an optimum field frequency, at which the increase in lasing power requires the minimum power of an external high-frequency generator, is established. The optimum field frequency is determined to be close to the electron plasma frequency corresponding to the optimal concentration of plasma electrons in the regime of excitation by a direct-curret discharge.