We have investigated the orientational distribution of a dilute colloidal dispersion of ferromagnetic spherocylinder particles for the case of a steady simple shear flow in a magnetic field parallel to the angular velocity vector of the shear flow. The results obtained are summarized as follows. When the flow field is dominant compared with the Brownian motion and the magnetic interactions, the particles rotate in the plane perpendicular to the magnetic field direction. As the magnetic field increases, the particles incline towards the magnetic direction,so that the viscosity is independent of the magnetic field and is zero.