The M1-transition probability of the 0.321 Mev level of V51 has been calculated on the basis of configuration mixing. The calculated values are satisfactory in comparison with experimental value which was recently measured by Delyagin and Preĭsa. In the calculations, the Rosenfeld mixture type of spin exchange forces is used for the two-body interaction between particles in the unfilled shell. For justification of our standpoint, the magnetic moment of V51 has been calculated. The result is almost in agreement with the experimental value.