The growth phenomena of adhered fine crystals on the surface of growing L-alanine crystals were investigated under homogeneous magnetic fields of 5 T and 0 T. Surface topography of grown crystals was observed using a differential interference microscope and an atomic force microscopy (AFM) system. We found that the direction of the adhered fine crystals could be controlled by the magnetic field. Crystal growth steps generated from the adhered crystals on a seed crystal under 5 T and 0 T were markedly different. The growth steps under the magnetic field were smooth in the [-210], [2-10] directions and rough in the [0 0 11, [00-1] directions. On the other hand, the growth steps under 0 T were rough and randomly spread over the surface of the seed crystal.