"Our country decided today to launch a countermeasure from 1 September over the Byrd Amendment of the United States," Trade Minister Shoichi Nakagawa said in a statement on Monday.
Japan will slap 15% retaliatory levies on US steel, Trade Ministry official Etsuo Sato said.
The percentage is in line with moves by Canada and the European Union, which have taken retaliatory actions against US products since 1 May over US legislation known as the Byrd Amendment, an anti-dumping law ruled illegal by the World Trade Organisation (WTO).
Tokyo made the decision after the Council on Customs, Tariff, Foreign Exchange and Other Transactions gave its approval on Monday.
The tariffs will amount to 5.7 billion yen ($51 million), said Sato.
The tariffs are the latest retaliation for the Byrd legislation, which redistributes levies on dumping - selling items abroad at less than the price in the domestic market - to US companies.
Japan and other countries including the European Union took the case to the WTO, which last year authorised sanctions amounting to 72% of the sums reaped by the US law.
The Nihon Keizai Shimbun said last week that the tariffs would
remain in place until Washington repealed its 2000 US law, which is named after US Senator Robert Byrd.