Prices for materials and other producer goods in Japan rose 5.8 percent in April from a year earlier.
That is the fourth straight month of slowing gains driven by declines in energy prices.
The preliminary April Producer Price Index figures were released Monday by the Bank of Japan. The gain marked the 26th month in a row of wholesale inflation.
Producer inflation peaked at a four-decade high in December 2022. The increases have moderated since then amid a drop in prices for crude oil and other forms of energy.
The Bank of Japan price index figures also showed import prices fell for first the time in 26 months in yen terms. Prices for goods brought into Japan dropped 2.9 percent in April from a year earlier.
Still, prices rose for 83 percent of items covered by the Corporate Goods Price Index.
More firms are passing on higher material costs to their business customers.