The Fukushima district court's verdict was the second time the government has been ruled liable for the meltdown in eastern Japan, the world's most serious nuclear accident since Chernobyl in 1986.
The court ordered the government and the operator Tokyo Electric Power Co (TEPCO) to pay a total of 500 million yen (USD 4.4 million) to the plaintiffs, in the biggest class- action suit so far.
The plaintiffs, local residents whose lives were ruined and property destroyed by the disaster, were awarded up to 360,000 yen (USD 3,198) each, according to a copy of the verdict obtained by AFP.
In March a court in the eastern city of Maebashi ruled that both the government and TEPCO were responsible.
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However, another court, in Chiba near Tokyo, ruled last month that only the operator was liable.
Around 12,000 people who fled due to radiation fears have filed various group lawsuits against the government and TEPCO.
Cases have revolved around whether the government and TEPCO, both responsible for disaster prevention measures, could have foreseen the scale of the tsunami.
Dozens of class-action lawsuits have been filed seeking compensation from the government.
Triggered by a 9.1-magnitude earthquake, the tsunami overwhelmed reactor cooling systems, sending three into meltdown at the plant.
Radiation was spewed over a wide area, leaving vast swathes of land uninhabitable in Japan's worst post-war disaster.