Experimental and analytical investigations have been made on unsaturated gain g
0of a CO
2electric-discharge convection laser, in which discharge current flow, gas flow, and the optical axis are mutually perpendicular. Stable glow discharges in sealed gas mixtures of CO
2, CO, N
2, and He were maintained at pressures up to 780 torr with an input power density of about 90 W/cm
3. The ratio of electric field to neutral particle density

was

V . cm
2and was independent of the total gas pressure

. The electron density in a positive column of the glow discharge was about

cm
-3. Detailed spatial distributions of g
0at a wavelength near 10.6 μm were measured in the pressure range from 100 to 780 torr. Measurements were also made on the current dependence of g
0and on the change in g
owith discharge time. The g
0distributions along the gas flow direction were found to agree with those calculated from the electron density distribution and the relaxation rate constant of the upper laser level on the basis of continuity equations for a two-level model. The integrated value of g
0along the flow direction was proportional to P
-0.8when

, electron density, and gas temperature were held constant. A maximum value of the g
0distribution, which was proportional to P
-0.3, was 0.14 percent/cm at 780 torr.