Microstructures of artificial superlattices of fcc-Fe/Cu (Au) having different magnetic properties have been studied by means of cross-sectional transmission electron microscopy (TEM). The superlattice made on a very flat substrate whose saturation magnetization was about 25 emu/g(Fe) constituted a flat film with the step of < 1 nm at the interface between Fe and Cu (Au). On the other hand, the film on a slightly rough substrate having a larger magnetization showed a wavy contrast with a width of several hundred nanometers and a height of several tens of nanometers reflecting the geometry of the substrate. At the interfaces a wavy contrast with a width of several tens of nanometers and a height of several nanometers was observed. The difference of the microstructures in these two samples was mainly this wavy geometry at the interface inside the superlattice. The observed microstructure must play an important role influencing the magnetic property of the superlattice.