The producer price index (PPI) stood at 102.92 in October, down 0.5 percent from the previous month, according to the Bank of Korea (BOK).
It marked the first slide in five months as the producer price for agricultural, livestock and fishery products tumbled 9.6 percent last month.
Price among suppliers for electricity, natural gas and tap water retreated 0.7 percent in October from a month ago.
The producer price for industrial products lost 0.1 percent on lower price for coal and oil products.
Services price was unchanged in October from a month earlier on lower cost for the finance and insurance and the information and communication services that offset higher cost for the eatery and lodging and the transportation services.