  A theory of fluctuations in two-band superconductor MgB$_{2}$ is developed.
Since the standard Ginzburg-Landau (GL) approach fails in description of its
properties, we generalize it basing on the microscopic theory of a two-band
superconductor. Calculating the microscopic fluctuation propagator, we build up
the nonlocal two-band GL functional and the corresponding time-dependent GL
equations. This allows us to calculate the main fluctuation observables such as
fluctuation specific heat and conductivity.
