The decay of Ni57 has been investigated in order to obtain detailed information about the level structure of the odd-even Co57. Lithium-drifted germanium detectors as well as standard scintillation-spectrometry techniques have been used. The levels at 1.46, 1.59, 1.75, and 2.62 MeV have been established with direct de-excitation to the Co57 ground state, in addition to the already known levels at energies of 1.37, 1.497, and 1.9 MeV. It has been confirmed that the 1.497-MeV level is the only one which decays by a (0.127-1.37)-MeV cascade of gamma rays. The various gamma-gamma coincidence studies have been performed; and based on these results, and on the ratios of electron capture to β+ decay, a decay scheme of Ni57 is proposed, and the results discussed in the light of the Coriolis coupling model. The half-life of the 1.497-MeV level has been measured as (0.60+/-0.05)×10-9 sec and an upper limit for the half-life of the 1.37-MeV level is given as ~2×10-10 sec.