Aikoku Maru (愛国丸) was an armed merchant cruiser of the Imperial Japanese Navy in World War II. The ship entered service in 1940, the ship was later converted to an ammunition ship. She was sunk in February 1944 during Operation Hailstone.

An armed merchantman is a merchant ship equipped with guns, usually for defensive purposes, either by design or after the fact. In the days of sail, piracy and privateers, many merchantmen would be routinely armed, especially those engaging in long distance and high value trade.