The growth patterns on the {100} surface of KBr crystal, growing in aq
ueous solution at low supersaturation (sigma = 1.0%), were observed in
situ with an optical microscope. Some growth steps appeared at the cr
ystal edges and then advanced toward the center of the {100} surface.
The growth steps were bunched and formed lines. They appeared as a com
plex growth pattern on the growing surface. The complexity of the grow
th step patterns increased with crystal growth, while the advance rate
of the growth steps decreased with it. The complexity was represented
as a fractal. The fractal dimension of the growth step patterns was c
alculated to be 0.87-1.27 during the observation.