
The decision from the Hiroshima High Court lifts an injunction handed down in December 2017 that ordered Shikoku not to restart the 890-megawatt No. 3 reactor at its Ikata power station in southern Japan.
The reactor has been shut since October 2017 for scheduled maintenance.
The plant is scheduled to restart on Oct 27, a spokesman for Shikoku said.
However, residents in nearby Oita prefecture have sought an injunction to halt the restart with the Oita district court, which will issue a ruling on Friday.
Residents have lodged injunctions against most nuclear plants across Japan. Some of the lower courts have sided with them on safety concerns, but the verdicts are usually overturned in higher courts.