Magnetization and Mössbauer spectroscopy measurements were performed for MnCo_{1−x}Fe_{x}Ge (x = 0.08, 0.12) to clarify its fundamental properties of the magnetism. The magnetic moments m for x = 0.08 was estimated to be 3.70 μB/f.u. at 10 K. The compound showed a first-order magnetic transition (FOMT) from the martensitic phase with high magnetic moment to the parent phase with low magnetic moment in the vicinity of Tt = 275 K with increasing temperature under magnetic field of μ0H = 1 T. From Mössbauer measurement for x = 0.12, the valence of Fe atom was found to be Fe2+. The obtained results were discussed on the basis of the mean-field calculation for the parent and martensitic phases.