Features of a competitive diffusion of individual alloying elements in high-temperature $\beta$-phase of titanium alloys of the metastable $\beta$-class under non-equilibrium conditions of continuous rapid heating are investigated using a few commercial alloys. As established, the rate of diffusion redistribution of alloying elements in $\beta$-phase depends not so much on their total concentration (expressed by the integral content of $\beta$-stabilizing elements in molybdenum equivalent $C^{\textrm{Mo}}_0$), but on the rates of diffusion of individual elements. Iron concentration is homogenized thought high-temperature $\beta$-phase at first, chromium concentration equalizes somewhat slower, and the concentration of $\beta$-stabilizers of isomorphic type (like vanadium or molybdenum) smoothes most slowly. This leads to the fact that, similarly to carbon steels, in the titanium alloys of metastable $\beta$-class under non-equilibrium conditions of rapid heating in the beginning the para- (partial) and then the ortho- (complete) equilibrium distributions are formed for $\beta$-stabilizers of eutectoid and isomorphic type, respectively.