The growth of L-alanine crystals in a magnetic field in a fluidized-bed crystallizer was investigated. Microscopic observations of the results of crystallization revealed that the c-axes of the L-alanine crystals moving in the solution were parallel to the direction of the applied magnetic field. Furthermore, the degree of orientation of the crystals was examined for various crystal sizes and the magnetic field induction. The surface topography of the grown crystals was observed under a differential interference microscope and an atomic force microscope (AFM). It was found that the orientation of the fine crystals adhered to the surface of the growing crystals and the surface topography of the crystals could be controlled by applying a magnetic field in the fluidized-bed crystallizer.