The Osaka District Court determined Monday that it is unconstitutional to set any age difference between widows and widowers for pension entitlement.

The ruling was on behalf of a 66-year-old former company employee in Osaka Prefecture who sought payment of a pension after his wife, a 51-year-old public high school teacher who committed suicide in 1998 after struggling with depression, was recognized as an official workplace casualty in 2010.

His demand was rejected in 2011 in accordance with the 1967 local public service accident compensation law, which stipulates a pension is provided to a widow whose husband's death results from an accident or is otherwise officially recognized regardless of her age, while a widower must be 60 or older in principle to receive a similar pension if he loses his wife in the same situations.

The plaintiff was 51 years old when his wife died.

In the ruling, the first of its kind, presiding Judge Kenji Nakagaito said it was a common practice when the law was enacted that husbands worked as regular employees and their wives stayed at home as full-time homemakers.

"But social situations have changed and many couples have double incomes now," he said. "When many male workers are working on a non-regular basis, it is not reasonable to recognize the eligibility of pension rights based on gender."

During the court hearings, the plaintiff argued that the current system is based on out-of-fashion family values whereby a husband works and a wife stays home, while the local pension authority claimed it is still reasonable to determine eligibility based on self-support capabilities as wage differences between men and women are still wide.