The invention relates to methods of manufacturing gas-discharge electron lamps, and neon tubes in particular. According to the invention, it is proposed, prior to carrying out vacuum treatment of the internal space of an electron lamp (1), to mount at least one of said glass capsules (2) in exhaust tube (5), in close proximity to an exposed electrode in such manner that the opening provided in metal container (4) is facing the working area of the lamp (1). Upon carrying out vacuum treatment and filling the internal space with an inert gas, the portion of exhaust tube (5) that contains capsule (2) disposed within metal container (4) is separated from evacuation unit (10), and this area is subjected to the local effect of a high-power electromagnetic radiation, thereby causing substantially instantaneous heating of metal container (4), which results in a rupture of glass capsule (2) and intense evaporation of the liquid mercury, thereby resulting in a directional flow of pure mercury vapor, which flow rapidly fills up said internal space of the tube through the opening provided in metal container (4). Such method permits to provide environmentally safe production and to eliminate contamination of mercury inside the working space of a lamp, which in turn allows carrying out precise dosing and introduction of calculated minimal amounts of mercury. In addition, the inventive method does not require application of special electrodes and might be used in any mass manufacture of commercial products, and neon tubes in particular.