It gave no other details. Japanese media reports said that Akano was 65 and that three other Japanese men are on death row in China for drug smuggling. Calls to the Supreme Court and to the High Court in Liaoning were not answered Tuesday.
Foreign Ministry spokeswoman Jiang Yu said the execution will deter drug smuggling.
"The legitimate rights and interests of the people concerned have been fully guaranteed," Jiang said. "We hope this case will not effect the normal development of China-Japan relations."
Japanese Prime Minister Yukio Hatoyama said before the execution that "the execution is regrettable, even considering legal differences" between Japan and China.
Mizuho Fukushima, leader of the left-leaning Social Democratic Party and Cabinet member of the Hatoyama government, said afterward: "I am extremely shocked. Of course, drug crimes are serious, but in Japan people don't get the death penalty for those."
Akano's case has attracted a lot less attention than the December execution in Xinjiang of a British man convicted of drug smuggling -- China's first execution of a European citizen in nearly 60 years.
China ignored personal appeals from British Prime Minister Gordon Brown not to execute 53-year-old Akmal Shaikh, whose family said he was mentally unstable. Brown said he was "appalled" by the execution, prompting a warning from Beijing that such comments threatened to damage ties.
Japan's Kyodo news agency said Akano was convicted in 2008 of attempting to smuggle 2.5 kilograms (4.8 pounds) of drugs from China to Japan in 2006.
Kyodo said the three other Japanese on death row could be executed within the next several days.
China executes more people every year than any other country for a range of crimes, including financial offenses.