We present results of theoretical modelling of dynamic of remagnetization of a dimer, consisting of two single-domain ferromagnetic particles immobilized in a non-magnetic medium. The model is based on the Fokker-Plank equation for the density of probability of a given orientation of the particle's magnetic moments. The classical asymptotic Kramers-Brown approach is generalized for the two particles problem. The results show that formation of the dimers leads to increase of the system magnetization and to significant growth of characteristic time of its remagnetization.