We present clear experimental evidence for the momentum-dependent heavy fermionic electronic structures of the 4f-based strongly correlated system CeNi2Ge2 by soft x-ray angle-resolved photoemission spectroscopy. A comparison between the experimental three-dimensional quasiparticle dispersion of LaNi2Ge2 and CeNi2Ge2 has revealed that heavy fermionic electronic structures are seen in the region surrounding a specific momentum. Furthermore, the wave vectors between the observed "heavy spots" are consistent with a result of neutron scattering reflecting magnetic correlations, which could be a trigger for the superconductivity in CeNi2Ge2.