Crystal growth rate of the ((1) over bar 20) and (011) faces of L-alanine from aqueous solution was investigated using a in situ optical microscope system when supercooling was 7degreesC and 2degreesC. The measurement were carried out in different positions of 60, 125, and 160 mm upper or lower from the magnet center where magnetic field intensity was 5 T. The aqueous solution laid in different positions of the magnet center experiences upward or downward magnetic force equal to 2.4 to 5.7% of its gravity(g). Crystal growth rate was found decreased with experiencing upward magnetic force and increased when the force is downward. Convection rate change by magnetic force may be considered as one of the reasons to this change: upward magnetic force decreases solution convection rate thus decreases crystal growth rate, vice versa.