The Hiroshima High Court on Friday overturned a lower court decision to exempt from punishment an Afghan asylum seeker, slapping a 300,000 yen fine on him.
Abdul Aziz, 30, had earlier seen his refugee application rejected by the Justice Ministry and had been indicted on a charge of violating the immigration law.
The Hiroshima District Court found him guilty in June but exempted him from any penalties, stating he could be recognized as a refugee due to the risks of persecution he faces in his home country.
Prosecutors appealed the ruling.
Under a provision of the immigration law, people recognized as refugees are exempt from punishment even if they are convicted of immigration-related charges.
According to the lower court ruling, Aziz is a member of the ethnic Hazara group, a minority group in the Central Asian country.
As a member of the Hezb-e Wahdat party, a Muslim Shiite party supporting the ethnic minority, he fought the majority Pashtun group in a civil war before fleeing the country.
Aziz decided to seek asylum in Japan after learning that Taliban members from the Pashtun group were pursuing him, the ruling said.
He landed at Fukuoka airport in June 2001 and entered Japan using a forged passport, the ruling said, adding that he made a living procuring auto parts for used cars.
Aziz applied for asylum with the Justice Ministry's Osaka Regional Immigration Bureau in November, but his bid was rejected in February.