A population inversion density on the Ti 551.4‐nm (3D01−3F2) transition in a N2‐laser‐pumped Ti‐vapor laser has been estimated from measurements of an optical gain on the laser transition, length of the laser medium, and temperature in the vapor to determine the linewidth. Ti vapor is generated by irradiation of a pulsed YAG laser light of 1 J/pulse energy and then the Ti atoms are optically pumped by a N2laser of 0.2 mJ/cm2intensity. It has been experimentally observed that, in pure Ti vapor, the population of Ti (3d24s2 3F2) is about 8×1013/cm3, the temperature in the vapor is about 9000 K, the population inversion on the 551.4‐nm transition is about 1.5×1011/cm3, and the absorption cross section of the N2‐laser light at 337.044 nm by a Ti atom is 3.0×10−15cm2.