Interferometric measurements were made of the electron and neutral particle densities in the active medium of a pulsed electric-discharge CO//2 laser. A Michelson interferometer was employed with an HCN probing laser emitting at a wavelength of 337 mu . The maximum electron density (about 1. 2 multiplied by 10**1**2 cm** minus **3) was reached in a time of approximately 1 mu sec and the duration of the current pulse was approximately 0. 5 mu sec. Ejection of the gas from the main discharge gap was observed at 40-60 mu sec after the discharge, and it reached a value of DELTA N/N equals 60-80%.