Lateral variation of In content in a 1.5 mum thick InxGa1-xAs (x congruent-to 0.2) epilayer grown on channeled GaAs (100) substrates having (755)A or (411)A slope regions by molecular beam epitaxy (MBE) was studied by the energy dispersive x-ray spectroscopy, with high spatial resolution (0.6 mum). Significantly peculiar migration of In atoms on the (41 I)A was observed. Experimental data of this work strongly suggest that In atoms migrate preferentially in one way, that is to say, they migrate much more in the [122BAR] direction than in the opposite [122BAR] direction on the (411)A plane during MBE growth. The migration length of In atoms on the (100) plane was 5 mum when InGaAs was grown at T(s) = 570-degrees-C and V/III = 30.