  Kagome lattices host flat bands due to their frustrated lattice geometry,
which leads to destructive quantum interference of electron wave functions.
Here, we report imaging of the kagome flat band localization in real-space
using scanning tunneling microscopy. We identify both the Fe3Sn kagome lattice
layer and the Sn2 honeycomb layer with atomic resolution in kagome
antiferromagnet FeSn. On the Fe3Sn lattice, at the flat band energy determined
by the angle resolved photoemission spectroscopy, tunneling spectroscopy
detects an unusual state localized uniquely at the Fe kagome lattice network.
We further show that the vectorial in-plane magnetic field manipulates the
spatial anisotropy of the localization state within each kagome unit cell. Our
results are consistent with the real-space flat band localization in the
magnetic kagome lattice. We further discuss the magnetic tuning of flat band
localization under the spin-orbit coupled magnetic kagome lattice model.
