Tokyo District Court on Thursday cleared the former Tokyo Electric Power executives of negligence over the 2011 Fukushima disaster.
According to the court, the authorities were aware of the possibility of a tsunami hitting the region,but the forecast was too uncertain for them to take action.
Prosecutors had sought 5-year prison terms for the three executives.
Environmental group Greenpeace slammed the court's decision, saying Japan's legal system had "once again failed to stand up for the rights" of victims of the crisis.
The public also did not welcome the decision.
"So as not to embarrass our children and future generations, I think we will start the fight again."
"How could they make this ruling. We cannot understand and cannot accept it. For the past eight and a half years, there are many people who were forced to evacuate from their homes, their hometown, and are still looking for a place to live."
The trial began back in 2017, conducted by state-appointed lawyers after prosecutors decided not to bring charges against the former executives.
The prosecutors' decision came despite a judicial review panel of ordinary citizens judging in 2015 that the executives should face trial.
Eight years ago, a magnitude 9.0 earthquake off Japan’s northeast coast triggered an enormous tsunami that overwhelmed TEPCO's Fukushima Daiichi Nuclear Power Plant, causing reactors to meltdown and forcing 160-thousand residents to be evacuated.
KIM Da-mi, Arirang News.