[NiFe] hydrogenase catalyzes the reversible cleavage of H2. The electrons produced by the H2 cleavage pass through three Fe–S clusters in [NiFe] hydrogenase to its redox partner. It has been reported that the Ni‐SIa, Ni‐C, and Ni‐R states of [NiFe] hydrogenase are involved in the catalytic cycle, although the mechanism and regulation of the transition between the Ni‐C and Ni‐SIa states remain unrevealed. In this study, the FT‐IR spectra under light irradiation at 138–198 K show that the Ni‐L state of [NiFe] hydrogenase is an intermediate between the transition of the Ni‐C and Ni‐SIa states. The transition of the Ni‐C state to the Ni‐SIa state occurred when the proximal [Fe4S4]p2+/+ cluster was oxidized, but not when it was reduced. These results show that the catalytic cycle of [NiFe] hydrogenase is controlled by the redox state of its [Fe4S4]p2+/+ cluster, which may function as a gate for the electron flow from the NiFe active site to the redox partner.