Japan's foreign exchange reserves at the end of April were up $5.18 billion from a month earlier to a record $406.7 billion, the Finance Ministry said Thursday.
The previous record of $405.7 billion was set at the end of October.
The increase stems primarily from a stronger euro against the dollar and rises in the prices of Japan's foreign bond holdings, a ministry official said.
The ministry also said Japan's monetary authority did not intervene in the currency market in the January-March period.
Japan remained the world's largest holder of foreign reserves for the 29th consecutive month, based on data available at the end of March.
The foreign exchange reserves consist of securities and deposits denominated in foreign currencies plus International Monetary Fund reserve positions, IMF special drawing rights, and gold.
Japan had $330.48 billion in foreign securities, up from $327.58 billion in March, and $60.64 billion in foreign currency deposits, up from $58.10 billion.
Of the deposits, $5.89 billion were at foreign central banks and the Switzerland-based Bank for International Settlements, $32.41 billion at Japanese banks, and $22.34 billion at other foreign banks.